*3.1. General Experimental Procedures*

All commercial reagents were purchased from Tokyo Chemical Industry, Tokyo, Japan. The glassware was dried in an oven (105 ◦C) before the experiment. Photochemical reactions were carried out using a commercially supplied LED (4W LED Filament GLS Blue, 220–240 V, EVE) and 18-W fluorescent light (100 V, HATAYA, Tokyo, Japan). All reactions were monitored by thin-layer chromatography (TLC) using aluminum silica gel 60 F254 (Merck, Darmstadt, Germany), and the TLC chromatogram was recorded under UV light at 254 and 365 nm. Flash column chromatographic purification was performed with silica gel (230–400 mesh) using a mixture of ethyl acetate and hexane as the mobile phase. Moreover, 1H and 13C NMR spectra were recorded on a Bruker ADVANCE NEO NMR spectrometer (Bruker, Massachusetts, MA, USA) at 400 and 100 MHz, respectively. Deuterated chloroform (CDCl3) was used as the internal standard for the 13C (77.0 ppm) and 1H (7.27 ppm) spectroscopic analyses. Infrared spectra were measured using a Perkin Frontier Fourier-Transform Infrared Spectrometer (PerkinElmer, Massachusetts, MA, USA). High-resolution mass spectrometry was conducted using a microTOF Bruker Daltonics mass spectrometer. Optical rotations were measured with a JASCO P-2000 polarimeter using a 1-mL cell with a

cell path length of 1 dm. The spectra of electronic circular dichroism were obtained using a JASCO J-815 CD spectrometer (JASCO, Maryland, MD, USA).
