The (2~+ 2? r)-photodimerizations of 2-phenylindene (l), 2-(4-methoxyphenyl) indene (9), and 5, lO-dihydroindeno [2, 1-a] indene (2) were investigated in a variety of homogeneous and micellar solvents. Four isomeric photodimem were formed from 1 and 9 syn-head-to-tail, syn-head-to-head, anti-head-btail, and anti-head-bhead. Relative yields of these as well as syn/anti-and head-to-tail (ht)/head-to-head (hh) ratios were determined in various solvents ...
