Tetrahydrophthalic anhydride and imide: remarkably efficient partners in photochemical [2 + 2] cycloaddition reactions with alkenols and alkynols
Abstract
Intermolecular photochemical [2 + 2] cycloaddition of a variety of alken- and alkyn-3-ols with 3,4,5,6-tetrahydrophthalic anhydride (THPA) and the related imide 4 gave the corresponding cyclobutanes and cyclobutenes in high yield, after relatively short irradiation times, with stereoselectivities as high as 10:1 for the cyclobutane examples.