All chemicals were purchased from commercial sources and used as received. Solvents were dried via passing through alumina columns using an Inert® system and were stored under nitrogen. Chromatographic purifications were performed under gradient or an isocratic regime using mesh 60 silica gel. 1H NMR and 13C NMR spectra were recorded at 300 K on a Bruker 400 MHz spectrometer using the solvent as internal standard (7.26 ppm for 1H NMR and 77.00 ppm for 13CNMR for CDCl3). Reported assignments were based on decoupling, COSY, NOESY, HSQC, and HMBC correlation experiments. The terms m, s, d, t, q, and quint represent multiplet, singlet, doublet, triplet, quadruplet, and quintuplet, respectively, and the term br means a broad signal. MS analyses were recorded on an Agilent Mass Spectrometer, and exact masses were recorded on an LTQ ORBITRAP XL Thermo Mass Spectrometer (electrospray sources).
4.1. General Procedure for the Alkyne Isomerization Leading to Allenes 1 (GP-1)
The desired enyne (1 equiv.) and THF (0.20 M) were sequentially added to a Schlenk tube equipped with a magnetic stirring bar. tBuOK (0.2 equiv.) was added and the resulting mixture was stirred at room temperature for 10 min. After complete conversion as monitored by TLC, 5 mL of a saturated NH4Cl solution was added. The mixture was extracted with EtOAc (31 × 5 mL); the organic layers were separated and dried over Na2SO4. The solution was concentrated under reduced pressure, and the crude product was purified by chromatography on silica gel (n-hexane/EtOAc gradient) to afford the corresponding enallene.
4.1.1. (E)-N-Benzyl-N-(propa-1,2-dien-1-yl)-3-(thiophen-2-yl)acrylamide
Enallene 1a was prepared following the general procedure GP-1 from the corresponding enyne (436.3 mg, 1.55 mmol). Yellow solid (292.7 mg, 67% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 7.91 (d, J = 15.0 Hz, 1H RotA, 1H RotB), 7.81 (t, J = 6.5 Hz, 1H RotA), 7.41–7.20 (m, 7H RotA, 7H RotB), 7.10–7.00 (m, 1H RotA, 1H RotB), 6.94–6.78 (m, 2H RotB), 6.62 (d, J = 14.9 Hz, 1H RotA), 5.36 (d, J = 6.3 Hz, 2H RotA, 2H RotB), 4.88–4.78 (m, 2H RotA, 2H RotB). 13C NMR (101 MHz, CDCl3) δ 202.7, 202.6, 164.8, 164.7, 140.2, 137.6, 137.2, 137.1, 136.6, 130.8, 128.9, 128.4, 128.1, 128.0, 127.9, 127.5, 127.1, 126.2, 115.7, 115.6, 100.1, 87.7, 86.8, 49.3, 48.3. ESI-MS calculated for C17H16NOS [M + H]+; 282.09 found 282.41.
4.1.2. (E)-N-(2-Bromobenzyl)-N-(propa-1,2-dien-1-yl)-3-(thiophen-2-yl)acrylamide
Enallene 1b was prepared following the general procedure GP-1 from the corresponding enyne (432.3 mg, 1.2 mmol). Yellow solid (309.8 mg, 72% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 7.98–7.87 (m, 1H RotA, 1H RotB), 7.83 (t, J = 6.4 Hz, 1H RotA), 7.65–7.52 (m, 1H RotA, 1H RotB), 7.45–6.85 (m, 6H RotA, 8H RotB), 6.44 (d, J = 15.0 Hz, 1H 1H RotA), 5.38–5.22 (m, 2H RotA, 2H RotB), 4.96–4.80 (m, 2H RotA, 2H RotB). 13C NMR (101 MHz, CDCl3) δ 202.2, 165.0, 164.7, 140.2, 140.1, 137.6, 137.0, 135.9, 132.8, 132.7, 131.0, 130.9, 129.0, 128.4, 128.2, 128.1, 128.0, 127.4, 127.2, 121.9, 115.1, 100.0, 87.9, 86.8, 49.5, 48.9. ESI-MS calculated for C17H15BrNOS [M + H]+; 360.01 found 360.46.
4.1.3. (E)-N-(Benzo[d][1,3]dioxol-5-ylmethyl)-N-(propa-1,2-dien-1-yl)-3-(thiophen-2-yl)acrylamide
Enallene 1c was prepared following the general procedure GP-1 from the corresponding enyne (292.8 mg, 0.9 mmol). Orange viscous oil (188.5 mg, 64% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 7.87 (d, J = 15.0 Hz, 1H RotA, 1H RotB), 7.79–7.71 (m, 1H RotA), 7.37–7.17 (m, 2H RotA, 2H RotB), 7.07–6.98 (m, 1H RotA, 1H RotB), 6.87–6.55 (m, 4H RotA, 5H RotB), 5.98–5.87 (m, 2H RotA, 2H RotB), 5.37 (d, J = 6.3 Hz, 2H RotA, 2H RotB), 4.74–4.64 (m, 2H RotA, 2H RotB). 13C NMR (101 MHz, CDCl3) δ 202.6, 202.5, 164.7, 164.6, 148.2, 147.7, 147.0, 146.7, 140.2, 137.1, 136.6, 131.4, 131.1, 130.8, 128.1, 127.9, 121.6, 119.5, 115.7, 115.6, 108.8, 108.5, 108.0, 106.8, 101.2, 100.9, 100.0, 87.8, 86.8, 49.0, 48.0. ESI-MS calculated for C18H16NO3S [M + H]+; 326.08 found 326.56.
4.1.4. (E)-N-Methyl-N-(propa-1,2-dien-1-yl)-3-(thiophen-2-yl)acrylamide
Enallene 1d was prepared following the general procedure GP-1 from the corresponding enyne (153.9 mg, 0.75 mmol). Orange viscous oil (87.1 mg, 57% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 7.93–7.78 (m, 1H RotA, 1H RotB), 7.73–7.64 (m, 1H RotA), 7.38–7.20 (m, 2H RotA, 2H RotB), 7.09–6.93 (m, 1H RotA, 2H RotB), 6.79–6.65 (m, 1H RotA, 1H RotB), 5.49–5.36 (m, 2H RotA, 2H RotB), 3.25–3.02 (m, 3H RotA, 3H RotB). 13C NMR (101 MHz, CDCl3) δ 202.8, 201.7, 164.8, 164.3, 140.3, 136.8, 136.1, 130.9, 130.7, 128.1, 127.8, 127.7, 115.4, 101.3, 100.3, 87.3, 86.7, 33.0, 31.8. ESI-MS calculated for C11H12NOS [M + H]+; 206.06 found 206.13.
4.1.5. (E)-N-Benzyl-3-(furan-2-ySl)-N-(propa-1,2-dien-1-yl)acrylamide
Enallene 1e was prepared following the general procedure GP-1 from the corresponding enyne (185.6 mg, 0.7 mmol). Orange solid (140.9 mg, 76% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 7.80 (t, J = 6.5 Hz, 1H RotA), 7.63–7.19 (m, 7H RotA, 7H RotB), 6.99–6.89 (m, 2H RotB), 6.73 (d, J = 15.0 Hz, 1H RotA), 6.64–6.56 (m, 1H RotA, 1H RotB), 6.53–6.42 (m, 1H RotA, 1H RotB), 5.39–5.29 (m, 2H RotA, 2H RotB), 4.90–4.79 (m, 2H RotA, 2H RotB). 13C NMR (101 MHz, CDCl3) δ 202.8, 202.4, 164.9, 151.5, 144.3, 137.6, 137.1, 131.1, 130.5, 128.8, 128.7, 128.4, 128.1, 128.0, 127.4, 127.1, 126.2, 114.8, 114.6, 114.3, 112.3, 100.2, 99.9, 87.6, 86.8, 49.2, 48.2. ESI-MS calculated for C17H16NO2 [M + H]+; 266.11 found 265.72.
4.1.6. (E)-N-Benzyl-3-(furan-2-yl)-N-(propa-1,2-dien-1-yl)acrylamide-2-d
Enallene 1f was prepared following the general procedure GP-1 from the corresponding enyne (234.4 mg, 0.88 mmol). Orange solid (155.9 mg, 67% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 7.80 (t, J = 6.4 Hz, 1H RotA), 7.61–7.53 (m, 1H RotA, 1H RotB, 7.52–7.17 (m, 6H RotA, 6H RotB), 6.98–6.91 (m, 1H RotB, 1H RotB non-deuterated 1f), 6.73 (d, J = 15.1 Hz, 1H RotA non-deuterated 1f), 6.64–6.55 (m, 1H RotA, 1H RotB), 6.51–6.42 (m, 1H RotA, 1H RotB), 5.39–5.27 (m, 2H RotA, 2H RotB), 4.88–4.79 (m, 2H RotA, 2H RotB). 13C NMR (101 MHz, CDCl3) δ 202.8, 202.4, 164.9, 151.5, 151.4, 144.3, 137.6, 137.1, 131.1, 131.0, 130.5, 130.4, 128.8, 128.4, 128.0, 127.4, 127.1, 126.2, 114.8, 114.6, 114.3, 114.2, 114.0 (t, J = 24.1 Hz), 112.3, 100.2, 99.9, 87.6, 86.8, 49.2, 48.1. ESI-MS calculated for C17H15DNO2 [M + H]+; 267.12 found 266.96.
4.1.7. (E)-N-(4-Fluorobenzyl)-3-(furan-2-yl)-N-(propa-1,2-dien-1-yl)acrylamide
Enallene 1g was prepared following the general procedure GP-1 from the corresponding enyne (311.6 mg, 1.1 mmol). Orange solid (189.6 mg, 61% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 7.77 (t, J = 6.4 Hz, 1H RotA), 7.60–7.52 (m, 1H RotA, 1H RotB), 7.45 (d, J = 22.8 Hz, 1H RotA, 1H RotB), 7.34–7.18 (m, 2H RotA, 2H RotB), 7.09–6.88 (m, 2H RotA, 4H RotB), 6.70 (d, J = 15.0 Hz, 1H RotA), 6.62–6.59 (m, 1H RotA, 1H RotB), 6.49–6.45 (m, 1H RotA, 1H RotB), 5.37–5.33 (m, 2H RotA, 2H RotB), 4.79 (s, 2H RotA, 2H RotB). 13C NMR (101 MHz, CDCl3) δ 202.7, 202.3, 164.9, 164.8, 163.3 (d, J = 8.3 Hz), 160.8 (d, J = 8.5 Hz), 151.5, 151.4, 144.4, 133.4, 132.8, 131.3, 130.6, 129.8, 129.7, 127.9, 127.8, 115.8, 115.6, 115.2, 115.1, 115.0, 114.7, 114.1, 114.0, 112.4, 100.1, 99.8, 87.7, 86.9, 48.5, 47.4. 19F NMR (565 MHz, CDCl3) δ -115.02 (q, J = 7.2 Hz, 1F RotA), -115.52 (q, J = 7.1 Hz, 1F RotB). ESI-MS calculated for C17H15FNO2 [M + H]+; 284.11 found 284.06.
4.1.8. (E)-3-(Furan-2-yl)-N-(3-methoxybenzyl)-N-(propa-1,2-dien-1-yl)acrylamide
Enallene 1h was prepared following the general procedure GP-1 from the corresponding enyne (295.3 mg, 1.0 mmol). Orange solid (222.6 mg, 75% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 7.79 (t, J = 6.4 Hz, 1H RotA), 7.56 (dd, J = 15.1, 3.7 Hz, 1H RotA, 1H RotB), 7.48 (s, 1H RotB), 7.41 (s, 1H RotA), 7.30–7.21 (m, 1H RotA, 1H RotB), 6.97–6.69 (m, 4H RotA, 5H RotB), 6.64–6.55 (m, 1H RotA, 1H RotB), 6.51–6.42 (m, 1H RotA, 1H RotB), 5.35 (d, J = 9.0 Hz, 2H RotA, 2H RotB), 4.81 (d, J = 9.0 Hz, 2H RotA, 2H RotB), 3.80 (s, 3H RotA, 3H RotB). 13C NMR (101 MHz, CDCl3) δ 202.7, 202.4, 164.9, 160.0, 159.7, 151.5, 144.3, 139.2, 138.8, 131.1, 130.5, 129.9, 129.3, 120.3, 118.4, 114.8, 114.6, 114.3, 113.6, 112.6, 112.5, 112.3, 112.0, 100.3, 99.9, 87.7, 86.8, 55.2, 49.1, 48.1. ESI-MS calculated for C18H18NO3 [M + H]+; 296.13 found 296.07.
4.1.9. (E)-N-Cyclopropyl-3-(furan-2-yl)-N-(propa-1,2-dien-1-yl)acrylamide
Enallene 1i was prepared following the general procedure GP-1 from the corresponding enyne (129.2 mg, 0.6 mmol). Brown oil (86.1 mg, 66% yield). 1H NMR (400 MHz, CDCl3) δ 7.49–7.46 (m, 3H), 7.18 (d, J = 15.3 Hz, 1H), 6.60 (d, J = 3.4 Hz, 1H), 6.48 (dd, J = 3.4, 1.8 Hz, 1H), 5.36 (d, J = 6.5 Hz, 2H), 2.74 (tt, J = 7.0, 3.8 Hz, 1H), 1.05–1.00 (m, 2H), 0.88–0.84 (m, 2H). 13C NMR (101 MHz, CDCl3) δ 203.6, 166.2, 151.7, 144.2, 129.7, 115.8, 114.5, 112.3, 99.6, 85.5, 28.0, 10.1. ESI-MS calculated for C13H14NO2 [M + H]+; 216.10 found 216.04.
4.1.10. (E)-3-(Benzo[b]thiophen-2-yl)-N-benzyl-N-(propa-1,2-dien-1-yl)acrylamide
Enallene 1j was prepared following the general procedure GP-1 from the corresponding enyne (334.4 mg, 1.0 mmol). Brown solid (128.5 mg, 38% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 7.99 (dd, J = 15.1, 3.2 Hz, 1H RotA, 1H RotB), 7.84–7.74 (m, 3H RotA, 2H RotB), 7.54–7.23 (m, 8H RotA, 8H RotB), 6.91–6.88 (m, 1H RotA, 1H RotB), 6.68 (d, J = 14.9 Hz, 1H RotB), 5.39 (d, J = 6.3 Hz, 2H RotA, 2H RotB), 4.85 (d, J = 14.5 Hz, 2H RotA, 2H RotB). 13C NMR (101 MHz, CDCl3) δ 202.7, 164.5, 164.4, 140.1, 139.9, 139.7, 137.6, 137.5, 137.14, 137.06, 128.9, 128.6, 128.4, 128.1, 127.6, 127.2, 126.3, 126.1, 124.9, 124.44, 122.37, 122.4, 118.3, 118.2, 100.1, 87.9, 86.8, 49.3, 48.4. ESI-MS calculated for C21H18NOS [M + H]+; 332.11 found 332.08.
4.1.11. (E)-3-(Benzo[b]thiophen-2-yl)-N-(3-methylbenzyl)-N-(propa-1,2-dien-1-yl)acrylamide
Enallene 1k was prepared following the general procedure GP-1 from the corresponding enyne (390.37 mg, 1.13 mmol). Yellow solid (226.3 mg, 58% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 8.03–7.95 (m, 1H RotA, 1H RotB), 7.86–7.71 (m, 3H RotA, 2H RotB), 7.50–7.06 (m, 7H RotA, 7H RotB), 6.94–6.86 (m, 2H RotB), 6.68 (d, J = 14.9 Hz, 1H RotA), 5.40 (d, J = 6.4 Hz, 2H RotA, 2H RotB), 4.86–4.76 (m, 2H RotA, 2H RotB), 2.41–2.33 (m, 3H RotA, 3H RotB). 13C NMR (101 MHz, CDCl3) δ 202.8, 202.7, 164.5, 164.4, 140.2, 139.9, 139.7, 138.7, 138.1, 137.5, 137.3, 137.1, 137.0, 128.84, 128.81, 128.7, 128.6, 128.51, 128.47, 128.4, 128.3, 128.0, 126.9, 126.1, 125.2, 125.1, 125.0, 124.9, 124.4, 123.4, 122.43, 122.36, 118.4, 118.2, 100.2, 87.8, 86.8, 49.3, 48.4, 21.5, 21.4. ESI-MS calculated for C22H20NOS [M + H]+; 346.13 found 345.88. (Partial decomposition was observed during the acquisition of NMR spectra).
4.1.12. (E)-3-(Benzofuran-2-yl)-N-benzyl-N-(propa-1,2-dien-1-yl)acrylamide
Enallene 1l was prepared following the general procedure GP-1 from the corresponding enyne (414.4 mg, 1.2 mmol). Pale yellow solid (248.8 mg, 60% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 7.81 (t, J = 6.4 Hz, 1H RotA), 7.69 (dd, J = 15.0, 8.2 Hz, 1H RotA, 1H RotB), 7.60 (dd, J = 11.4, 7.7 Hz, 1H RotA, 1H RotB), 7.57–7.19 (m, 8H RotA, 8H RotB), 7.03–6.99 (m, 1H RotA, 2H RotB), 6.94 (d, J = 10.2 Hz, 1H RotA, 1H RotB), 5.39–5.34 (m, 2H RotA, 2H RotB), 4.89 (s, 2H RotA, 2H RotB). 13C NMR (101 MHz, CDCl3) δ 202.9, 202.5, 164.5, 155.4, 153.0, 152.9, 137.5, 137.0, 131.4, 130.7, 128.8, 128.5, 128.4, 128.0, 127.5, 127.2, 126.32, 126.28, 123.3, 121.8, 117.3, 117.2, 111.3, 111.2, 110.9, 100.2, 99.8, 87.7, 86.9, 49.3, 48.3. ESI-MS calculated for C21H17NNaO2 [M + Na]+; 338.12 found 338.52.
4.1.13. (E)-N-Benzyl-3-(3-methylthiophen-2-yl)-N-(propa-1,2-dien-1-yl)acrylamide
Enallene 1m was prepared following the general procedure GP-1 from the corresponding enyne (295.4 mg, 1 mmol). Brown solid (236.3 mg, 80% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 8.03–7.93 (m, 1H RotA, 1H RotB), 7.82 (t, J = 6.4 Hz, 1H RotA), 7.41–7.17 (m, 6H RotA, 6H RotB), 6.94–6.83 (m, 1H RotA, 2H RotB), 6.76 (d, J = 15.0 Hz, 1H RotB), 6.55 (d, J = 14.9 Hz, 1H RotA), 5.37 (d, J = 6.3 Hz, 2H RotA, 2H RotB), 4.88–4.77 (m, 2H RotA, 2H RotB), 2.40–2.30 (m, 3H RotA, 3H RotB). 13C NMR (101 MHz, CDCl3) δ 202.7, 202.6, 165.05, 164.95, 141.2, 137.7, 137.3, 135.5, 135.1, 134.3, 131.3, 128.8, 128.4, 128.0, 127.5, 127.1, 126.4, 126.3, 114.8, 114.5, 100.2, 87.7, 86.8, 49.3, 48.3, 14.2. ESI-MS calculated for C17H18NOS [M + H]+; 296.11 found 295.67.
4.1.14. (E)-N-Benzyl-N-(propa-1,2-dien-1-yl)-3-(thiophen-3-yl)acrylamide
Enallene 1n was prepared following the general procedure GP-1 from the corresponding enyne (281.4 mg, 1 mmol). Orange oil (202.6 mg, 72% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, CDCl3) δ 7.83–7.77 (m, 2H RotA, 1H RotB), 7.52–7.26 (m, 7H RotA, 8H RotB), 7.16 (d, J = 5.2 Hz, 1H RotA), 6.93–6.83 (m, 2H RotB), 6.62 (d, J = 15.2 Hz, 1H RotA), 5.35 (d, J = 6.4 Hz, 2H RotA, 2H RotB), 4.84 (d, J = 12.0 Hz, 2H RotA, 2H RotB). 13C NMR (101 MHz, CDCl3) δ 202.7, 202.4, 165.3, 165.2, 138.2, 138.1, 137.6, 137.3, 128.9, 128.4, 128.0, 127.9, 127.7, 127.5, 127.1, 126.9, 126.8, 126.1, 125.1, 116.6, 116.5, 100.2, 100.1, 87.7, 86.8, 49.3, 48.2. ESI-MS calculated for C17H16NOS [M + H]+; 282.09 found 281.63.
4.1.15. (E)-N-Benzyl-3-(1-benzyl-1H-pyrrol-2-yl)-N-(propa-1,2-dien-1-yl)acrylamide
Enallene 1o was prepared following the general procedure GP-1 from the corresponding enyne (212.6 mg, 0.6 mmol). Orange oil (98.2 mg, 46% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, Acetone-d6) δ 7.72–7.64 (m, 2H RotA, 2H RotB), 7.34–7.26 (m, 9H RotA, 9H RotB), 7.13–7.06 (m, 3H RotA, 3H RotB), 7.00–6.94 (m, 1H RotA), 6.75–6.67 (m, 1H RotA, 2H RotB), 6.25–6.19 (m, 1H RotA, 1H RotB), 5.40–5.31 (m, 4H RotA, 4H RotB), 4.83–4.77 (m, J = 8.6 Hz, 2H RotA, 2H RotB). 13C NMR (101 MHz, Acetone-d6) δ 202.7, 202.1, 164.5, 138.5, 138.1, 132.0, 129.5, 128.7, 128.5, 128.3, 127.6, 127.4, 127.1, 126.7, 126.6, 126.3, 121.4, 111.9, 111.8, 109.3, 100.4, 99.6, 86.8, 85.9, 50.2, 49.7, 48.3, 47.3. ESI-MS calculated for C24H23N2O [M + H]+; 355.18 found 355.10. (Partial decomposition was observed during the acquisition of NMR spectra).
4.1.16. (E)-N-Benzyl-3-(1-methyl-1H-indol-2-yl)-N-(propa-1,2-dien-1-yl)acrylamide
Enallene 1p was prepared following the general procedure GP-1 from the corresponding enyne (164.2 mg, 0.5 mmol). Orange solid (79.4 mg, 48% yield). Two rotamers were observed due to the dynamic rotation of the amide. 1H NMR (400 MHz, Acetone-d6) δ 7.93–7.81 (m, J = 19.8, 10.0 Hz, 1H RotA, 2H RotB), 7.58–6.96 (m, 12H RotA, 11H RotB), 5.39 (d, J = 6.4 Hz, 2H RotA, 2H RotB), 4.91 (d, J = 43.3 Hz, 2H RotA, 2H RotB), 3.89 (s, 3H RotB), 3.80 (s, 3H RotA). 13C NMR (101 MHz, Acetone-d6) δ 207.9, 207.4, 169.2, 144.3, 143.4, 140.9, 137.2, 136.9, 133.9, 133.8, 133.4, 133.0, 133.0, 132.8, 132.5, 132.4, 131.5, 128.3, 126.1, 125.3, 122.6, 122.4, 115.1, 114.1, 108.2, 105.6, 104.9, 92.3, 91.3, 53.7, 52.7, 34.5. ESI-MS calculated for C22H21N2O [M + H]+; 329.17 found 329.60. (Partial decomposition was observed during the acquisition of NMR spectra).
4.2. General Procedure for the Photocatalytic Reaction Leading to Products 2 (GP-2)
To a vial charged with substrate 1 (1 equiv., 0.2 mmol) and Ir(p-F-ppy)3 (1 mol%), dry DCM (0.1 M) was added through a syringe. The solution was transferred into an NMR tube capped with a rubber septum, and it was placed in an oil bath kept at 40 °C and irradiated with LED stripes for 3 h. Conversion was monitored by TLC, and the mixture was then concentrated in vacuo. The residue was purified by chromatography on silica gel; the catalyst was removed using toluene as an eluent prior to the separation of the desired products (N-hexane/EtOAc, under gradient).
4.2.1. 1-Benzyl-1,4,8a,8b-tetrahydro-2H-thieno [2,3-g]indol-2-one
Product 2a was prepared following the general procedure GP-2 from the corresponding enallene (56.7 mg, 0.2 mmol; 392.1 mg, 1.39 mmol). White solid (35.7 mg, 63% yield; 205.9 mg, 52%, 9 h of irradiation). 1H NMR (400 MHz, CDCl3) δ 7.39–7.19 (m, 5H), 6.33 (dd, J = 6.4, 2.6 Hz, 1H), 6.07 (s, 1H), 5.76 (dd, J = 6.4, 1.4 Hz, 1H), 5.67 (q, J = 3.4 Hz, 1H), 5.15 (d, J = 15.8 Hz, 1H), 4.48 (d, J = 15.8 Hz, 1H), 3.91 (d, J = 10.3 Hz, 1H), 3.63–3.55 (m, 1H), 3.46–3.27 (m, 2H). 13C NMR (101 MHz, CDCl3) δ 172.3, 157.3, 137.6, 137.5, 128.9, 127.5, 127.4, 127.3, 121.2, 121.1, 115.6, 62.4, 56.1, 45.4, 28.8. ESI-HRMS calculated for C17H16NOS [M + H]+; 282.0948 found 282.0955.
4.2.2. 1-(2-Bromobenzyl)-1,4,8a,8b-tetrahydro-2H-thieno [2,3-g]indol-2-one
Product 2b was prepared following the general procedure GP-2 from the corresponding enallene (71.6 mg, 0.2 mmol). White solid (39.4 mg, 55% yield). 1H NMR (400 MHz, CDCl3) δ 7.58 (dd, J = 7.9, 1.3 Hz, 1H), 7.32–7.24 (m, 1H), 7.19–7.08 (m, 2H), 6.29 (dd, J = 6.4, 2.6 Hz, 1H), 6.11 (s, 1H), 5.70 (q, J = 3.5 Hz, 1H), 5.58–5.53 (m, 1H), 4.93 (d, J = 17.0 Hz, 1H), 4.81 (d, J = 17.0 Hz, 1H), 4.02 (d, J = 10.3 Hz, 1H), 3.64–3.56 (m, 1H), 3.49–3.33 (m, 2H). 13C NMR (101 MHz, CDCl3) δ 172.4, 157.7, 137.6, 136.3, 133.0, 128.9, 128.2, 127.9, 127.4, 122.3, 121.1, 115.5, 63.6, 56.0, 45.8, 28.8. ESI-HRMS calculated for C17H15BrNOS [M + H]+; 360.0053 found 360.0051.
4.2.3. 1-(Benzo[d][1,3]dioxol-5-ylmethyl)-1,4,8a,8b-tetrahydro-2H-thieno [2,3-g]indol-2-one
Product 2c was prepared following the general procedure GP-2 from the corresponding enallene (65.7 mg, 0.2 mmol). White solid (33.3 mg, 51% yield). 1H NMR (600 MHz, CDCl3) δ 6.74 (d, J = 7.8 Hz, 1H), 6.69–6.64 (m, 2H), 6.33 (dd, J = 6.3, 2.6 Hz, 1H), 6.02 (s, 1H), 5.93 (s, 2H), 5.77 (dd, J = 6.4, 1.4 Hz, 1H), 5.65 (q, J = 3.9 Hz, 1H), 5.03 (d, J = 15.6 Hz, 1H), 4.34 (d, J = 15.6 Hz, 1H), 3.88 (d, J = 10.3 Hz, 1H), 3.58–3.52 (m, 1H), 3.38 (dt, J = 22.1, 4.1 Hz, 1H), 3.30 (dq, J = 22.0, 4.1 Hz, 1H). 13C NMR (101 MHz, CDCl3) δ 172.3, 157.4, 148.2, 147.0, 137.6, 131.3, 127.4, 121.2, 121.1, 120.6, 115.6, 108.4, 107.9, 101.1, 62.3, 56.1, 45.2, 28.7. ESI-HRMS calculated for C18H16NO3S [M + H]+; 326.0846 found 326.0851.
4.2.4. 1-Methyl-1,4,8a,8b-tetrahydro-2H-thieno [2,3-g]indol-2-one
Product 2d was prepared following general procedure GP-2 from the corresponding enallene (40.5 mg, 0.2 mmol). White solid (16.9 mg, 42% yield). 1H NMR (400 MHz, Acetone-d6) δ 6.58 (dd, J = 6.4, 2.6 Hz, 1H), 6.11–6.07 (m, 1H), 5.90 (q, J = 1.6 Hz, 1H), 5.76–5.72 (m, 1H), 3.94 (d, J = 10.3 Hz, 1H), 3.56–3.48 (m, 1H), 3.41–3.36 (m, 2H), 3.08 (s, 3H). 13C NMR (101 MHz, Acetone-d6) δ 170.7, 156.7, 137.3, 126.8, 121.8, 120.8, 115.9, 64.3, 56.5, 28.14, 28.06. ESI-HRMS calculated for C11H12NOS [M + H]+; 206.0635 found 206.0639.
4.2.5. 1-Benzyl-1,4,8a,8b-tetrahydro-2H-furo [2,3-g]indol-2-one
Product 2e was prepared following general procedure GP-2 from the corresponding enallene (53.0 mg, 0.2 mmol). White solid (27.6 mg, 52% yield). 1H NMR (400 MHz, CDCl3) δ 7.40–7.20 (m, 5H), 6.53–6.49 (m, 1H), 6.09–6.05 (m, 1H), 5.23–5.18 (m, 2H), 5.03 (d, J = 15.6 Hz, 1H), 4.47 (d, J = 15.6 Hz, 1H), 3.85 (d, J = 9.4 Hz, 1H), 3.44–3.34 (m, 2H), 3.32–3.21 (m, 1H). 13C NMR (101 MHz, CDCl3) δ 172.1, 157.6, 154.7, 147.4, 137.6, 128.8, 127.53, 127.47, 121.5, 103.3, 94.8, 63.6, 47.8, 45.0, 25.2. ESI-HRMS calculated for C17H16NO2 [M + H]+; 266.1176 found 266.1170. (Partial decomposition was observed during the acquisition of NMR spectra).
4.2.6. 1-Benzyl-1,4,8a,8b-tetrahydro-2H-furo [2,3-g]indol-2-one-3-d
Product 2f was prepared following the general procedure GP-2 from the corresponding enallene (53.3 mg, 0.2 mmol). White solid (27.2 mg, 51% yield). 1H NMR (600 MHz, CDCl3) δ 7.34–7.17 (m, 5H), 6.49–6.46 (m, 1H), 6.03 (brs, 1H non-deuterated 2f), 5.19–5.15 (m, 2H), 4.99 (d, J = 15.6 Hz, 1H), 4.43 (d, J = 15.6 Hz, 1H), 3.81 (d, J = 9.8 Hz, 1H), 3.39–3.31 (m, 2H), 3.27–3.19 (m, 1H). 13C NMR (101 MHz, CDCl3) δ 172.1, 157.6 (non-deuterated 2f), 157.4, 154.7, 147.3, 137.7, 128.8, 127.52, 127.46, 121.5 (non-deuterated 2f), 103.3, 94.8, 63.59 (non-deuterated 2f), 63.56, 47.8, 45.0, 25.22 (non-deuterated 2f), 25.19. ESI-HRMS calculated for C17H15DNO2 [M + H]+; 267.1239 found 267.1243. (Partial decomposition was observed during the acquisition of NMR spectra).
4.2.7. 1-(4-Fluorobenzyl)-8a,8b-dihydro-1H-furo [2,3-g]indol-2(4H)-one
Product 2g was prepared following the general procedure GP-2 from the corresponding enallene (56.7 mg, 0.2 mmol). Pale yellow solid (29.4 mg, 52% yield). 1H NMR (400 MHz, CDCl3) δ 7.24–7.21 (m, 2H), 7.05–7.00 (m, 2H), 6.53 (dd, J = 3.0, 2.1 Hz, 1H), 6.06 (dt, J = 2.3, 1.2 Hz, 1H), 5.23–5.19 (m, 2H), 4.98 (d, J = 15.5 Hz, 1H), 4.43 (d, J = 15.6 Hz, 1H), 3.82 (d, J = 9.3 Hz, 1H), 3.42–3.34 (m, 2H), 3.31–3.22 (m, 1H). 13C NMR (101 MHz, CDCl3) δ 172.1, 163.4, 161.0, 157.7, 154.6, 147.6, 133.5, 133.4, 129.2, 121.5, 115.8, 115.6, 103.2, 94.9, 63.6, 47.7, 44.3, 25.2. 19F NMR (565 MHz, CDCl3) δ -114.78 (td, J = 8.7, 4.4 Hz). ESI-HRMS calculated for C17H15FNO2 [M + H]+; 284.1082 found 284.1081.
4.2.8. 1-(3-Methoxybenzyl)-8a,8b-dihydro-1H-furo [2,3-g]indol-2(4H)-one
Product 2h was prepared following the general procedure GP-2 from the corresponding enallene (59.1 mg, 0.2 mmol). White solid (29.3 mg, 50% yield). 1H NMR (400 MHz, CDCl3) δ 7.25 (t, J = 7.8 Hz, 1H), 6.84–6.78 (m, 3H), 6.52 (dd, J = 3.0, 2.1 Hz, 1H), 6.06 (dt, J = 2.3, 1.2 Hz, 1H), 5.23–5.20 (m, 2H), 4.99 (d, J = 15.6 Hz, 1H), 4.44 (d, J = 15.6 Hz, 1H), 3.86 (dd, J = 9.3, 1.4 Hz, 1H), 3.80 (s, 3H), 3.43–3.35 (m, 2H), 3.30–3.21 (m, 1H). 13C NMR (101 MHz, CDCl3) δ 172.0, 160.0, 157.6, 154.7, 147.4, 139.3, 129.8, 121.5, 119.7, 113.1, 112.8, 103.4, 94.8, 63.6, 55.3, 47.8, 44.9, 25.2. ESI-HRMS calculated for C18H18NO3 [M + H]+; 296.1282 found 296.1288.
4.2.9. 1-Cyclopropyl-8a,8b-dihydro-1H-furo [2,3-g]indol-2(4H)-one
Product 2i was prepared following the general procedure GP-2 from the corresponding enallene (43.1 mg, 0.2 mmol). Ocher solid (19.3 mg, 44% yield). 1H NMR (400 MHz, Acetone-d6) δ 6.76 (dd, J = 3.0, 2.3 Hz, 1H), 5.80 (dt, J = 2.4, 1.3 Hz, 1H), 5.77 (ddd, J = 3.2, 2.2, 1.1 Hz, 1H), 5.20 (dddd, J = 4.8, 3.8, 2.8, 1.2 Hz, 1H), 3.90 (dd, J = 9.9, 1.3 Hz, 1H), 3.47–3.39 (m, 1H), 3.37–3.22 (m, 2H), 2.65–2.59 (m, 1H), 0.94–0.87 (m, 1H), 0.82–0.74 (m, 3H). 13C NMR (101 MHz, Acetone-d6) δ 170.9, 157.0, 155.1, 146.8, 121.5, 104.6, 94.8, 64.3, 48.0, 24.7, 23.0, 7.7, 4.6. ESI-HRMS calculated for C13H14NO2 [M + H]+; 216.1020 found 216.1013.
4.2.10. 1-Benzyl-10b,10c-dihydro-1H-benzo [4,5]thieno [2,3-g]indol-2(4H)-one
Product 2j was prepared following the general procedure GP-2 from the corresponding enallene (66.3 mg, 0.2 mmol). Pale brown solid (42.1 mg, 63% yield). 1H NMR (400 MHz, Acetone-d6) δ 7.51 (dd, J = 7.7, 1.0 Hz, 1H), 7.31–7.23 (m, 5H), 7.16–7.08 (m, 3H), 6.11 (dt, J = 2.2, 1.1 Hz, 1H), 5.83 (dt, J = 5.0, 3.1 Hz, 1H), 5.31 (d, J = 15.9 Hz, 1H), 4.59 (d, J = 15.9 Hz, 1H), 4.23–4.18 (m, 2H), 3.56–3.49 (m, 1H), 3.44–3.35 (m, 1H). 13C NMR (101 MHz, Acetone-d6) δ 173.9, 160.2, 139.9, 138.0, 136.9, 136.8, 128.7, 128.6, 127.3, 127.1, 126.4, 124.6, 121.9, 120.8, 115.8, 63.5, 56.0, 47.0. ESI-HRMS calculated for C21H18NOS [M + H]+; 332.1104 found 332.1102.
4.2.11. 1-(3-Methylbenzyl)-1,4,10b,10c-tetrahydro-2H-benzo [4,5]thieno [2,3-g]indol-2-one
Product 2k was prepared following the general procedure GP-2 from the corresponding enallene (45.6 mg, 0.13 mmol). White solid (20.3 mg, 45% yield). 1H NMR (400 MHz, CDCl3) δ 7.45 (d, J = 7.7 Hz, 1H), 7.30–7.20 (m, 2H), 7.18–7.10 (m, 2H), 7.04 (d, J = 7.6 Hz, 1H), 6.86–6.79 (m, 2H), 6.13 (s, 1H), 5.76–5.73 (m, 1H), 5.40 (d, J = 15.5 Hz, 1H), 4.47 (d, J = 15.6 Hz, 1H), 4.16–4.11 (m, 2H), 3.54–3.45 (m, 1H), 3.39–3.29 (m, 1H), 2.28 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 174.9, 160.2, 140.0, 138.5, 137.6, 137.1, 136.3, 128.8, 128.6, 128.3, 128.2, 126.5, 124.6, 122.1, 121.3, 114.8, 63.7, 56.0, 47.4, 28.9, 21.4. ESI-HRMS calculated for C22H20NOS [M + H]+; 346.1261 found 346.1266.
4.2.12. 1-Benzyl-10b,10c-dihydro-1H-benzofuro [2,3-g]indol-2(4H)-one
Product 2l was prepared following the general procedure GP-2 from the corresponding enallene (63.1 mg, 0.2 mmol). Pale orange solid (28.0 mg, 45% yield). 1H NMR (400 MHz, Acetone-d6) δ 7.52 (d, J = 7.4 Hz, 1H), 7.33–7.21 (m, 6H), 7.00 (td, J = 7.6, 1.1 Hz, 1H), 6.95 (dd, J = 8.1, 1.0 Hz, 1H), 6.13 (dt, J = 2.4, 1.2 Hz, 1H), 5.38 (dt, J = 5.6, 2.9 Hz, 1H), 5.26 (d, J = 16.1 Hz, 1H), 4.76 (d, J = 16.1 Hz, 1H), 4.19 (dd, J = 9.9, 1.2 Hz, 1H), 4.13–4.09 (m, 1H), 3.50 (dddd, J = 21.3, 4.4, 2.0, 0.9 Hz, 1H), 3.39–3.31 (m, 1H). 13C NMR (101 MHz, Acetone-d6) δ 172.8, 159.2, 158.6, 154.3, 138.2, 129.3, 128.6, 127.2, 127.1, 126.5, 125.6, 122.1, 121.5, 109.8, 95.3, 63.2, 48.4, 45.9, 24.8. ESI-HRMS calculated for C21H18NO2 [M + H]+; 316.1333 found 316.1337.
4.2.13. 1-Benzyl-8a-methyl-8a,8b-dihydro-1H-thieno [2,3-g]indol-2(4H)-one
Product 2m was prepared following the general procedure GP-2 from the corresponding enallene (59.1 mg, 0.2 mmol). Pale yellow solid (42.2 mg, 71% yield). 1H NMR (400 MHz, CDCl3) δ 7.35–7.21 (m, 5H), 6.27 (d, J = 6.3 Hz, 1H), 6.10 (dt, J = 2.5, 1.3 Hz, 1H), 5.85 (dd, J = 6.4, 1.0 Hz, 1H), 5.64–5.62 (m, 1H), 5.29 (d, J = 15.6 Hz, 1H), 4.21 (d, J = 15.6 Hz, 1H), 4.07 (s, 1H), 3.42–3.32 (m, 1H), 3.33–3.25 (m 1H), 0.93 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 173.0, 156.3, 143.3, 137.2, 128.8, 127.7, 127.6, 127.4, 124.6, 121.8, 115.2, 65.0, 55.7, 45.2, 28.1, 18.4. ESI-HRMS calculated for C18H18NOS [M + H]+; 296.1104 found 296.1101.
4.2.14. 1,6-Dibenzyl-4,5,6,8-tetrahydropyrrolo [3,4-f]indol-7(1H)-one
Product 2o was prepared following the general procedure GP-2 from the corresponding enallene (70.9 mg, 0.2 mmol). White solid (40.4 mg, 57% yield). 1H NMR (400 MHz, Acetone-d6) δ 7.36–7.25 (m, 8H), 7.13–7.10 (m, 2H), 6.84 (d, J = 2.8 Hz, 1H), 5.99 (d, J = 2.8 Hz, 1H), 5.18 (s, 2H), 4.62 (s, 2H), 3.88 (t, J = 2.2 Hz, 2H), 3.47 (t, J = 6.8 Hz, 2H), 3.27–3.20 (m, 2H). 13C NMR (101 MHz, Acetone-d6) δ 170.3, 149.6, 139.1, 138.5, 128.6, 128.4, 127.8, 127.1, 126.6, 124.4, 121.4, 113.9, 105.7, 52.0, 49.9, 45.3, 24.5, 19.6. ESI-HRMS calculated for C24H23N2O [M + H]+; 355.1805 found 355.1804.
4.2.15. 2-Benzyl-5-methyl-1,2,5,10-tetrahydropyrrolo [3,4-b]carbazol-3(4H)-one
Product 2p was prepared following the general procedure GP-2 from the corresponding enallene (49.3 mg, 0.15 mmol). White solid (36.3 mg, 74% yield). 1H NMR (400 MHz, CDCl3) δ 7.49 (d, J = 7.8 Hz, 1H), 7.40–7.22 (m, 7H), 7.15–7.11 (m, 1H), 4.74 (s, 2H), 3.92 (d, J = 8.4 Hz, 2H), 3.74 (s, 3H), 3.67 (s, 4H). 13C NMR (101 MHz, CDCl3) δ 171.1, 149.1, 137.5, 132.8, 128.84, 128.80, 128.1, 127.6, 126.1, 121.3, 119.1, 117.8, 108.9, 105.0, 52.6, 46.2, 29.5, 23.4, 20.4. ESI-HRMS calculated for C22H21N2O [M + H]+; 329.1649 found 329.1646.