Substituent effects on the bridging modes of photochemical rearrangements of pyrazino-, quinoxalino-, and benzoquinoxalinobarrelenes
作者:Ann-Cheng Chen、Sheng-Yunn Lin、Nelson R. Villarante、Gary J. Chuang、Te-Chun Wu、Chun-Chen Liao
DOI:10.1016/j.tet.2008.06.054
日期:2008.9
multiplicities of photoreactants upon excitation. Irradiation of pyrazinobarrelene 4a furnished almost equal amounts of photoproducts derived from DPM (vinyl–vinyl bridging) and ADPM (aryl–vinyl bridging) pathways. Pyrazinobarrelenes 4b–d underwent chemoselective rearrangements via the ADPM route. In the case of quinoxalinobarrelenes 5a–c and benzoquinoxalinobarrelenes 6b,c, vinyl–vinyl bridging was strongly