Tributyl-[(Z)-5-phenyl-2-penten-2-yl]stannane

The general part of the experimental section [1] has been presented elsewhere. The Grignard solution prepared from magnesium turnings (0.11 g, 4.4 mmol) and (Z)-2-bromo-5-phenyl-2-pentene (0.90 g, 4 mmol) in dry tetrahydrofuran (15 ml) was decanted via double-ended needle from the excess magnesium, and titrated with tributyltin chloride until the solution decolourised. The resulting solution was stirred at room temperature for 1 hour and the solvent was removed under reduced pressure. The residue was partitioned between ether (30 ml) and water (30 ml). The ether extract was washed with brine (50 ml), dried (Na₂SO₄), filtered and evaporated under reduced pressure. The crude product was Kugelrohr distilled to yield tributyl-[(Z)-5-phenyl-2-penten-2-yl]stannane (1.13 g, 59%) as a colourless oil.

B.p. 180°/0.03 mmHg

IR (CDCl3) 2958(s), 2927(s), 2872, 2858, 1454, 1414, 1377, 1078, 698 cm^-1.

¹H-NMR (400 MHz, CDCl₃) 0.82-0.96 (15H, m, 3xCH₂ and 3xCH₃), 1.31 (6H, m, 3xCH₂), 1.47 (6H, m, 3xCH₂), 1.89 (3H, dt, J 1.7, 1.2 Hz, J119Sn,H and J_117Sn,H give average of 43 Hz, CH₃), 2.28 (2H, m, CH₂), 2.65 (2H, bt, J 7.8 Hz, Ph-CH₂), 6.09 (1H, tq, J 7.2, 1.7 Hz, J119Sn,H and J_117Sn,H give average of 133 Hz, =CH), 7.16-7.33 (5H, m, ArH). Stereochemistry confirmed by n.O.e. difference spectroscopy. Irradiation at 1.89 produced a 3% n.O.e. at 6.09 . Irradiation at 6.09 produced an 9% n.O.e. at 1.89 (also 5% at 2.28, 4% at 2.65).

¹³C-NMR (100 MHz, CDCl₃) 10.05 (CH₃), 13.83 (CH₂), 27.52 (CH₃), 27.52 (CH₂), 29.34, 36.79, 37.00 (CH₂), 125.6, 128.2, 128.3 (ArCH), 138.7 (quat, C2), 139.7 (=CH),, 141.9 (quat, C1').

Acknowledgment: The authors gratefully acknowledge financial support from the Australian Research Council and The University of Sydney.