vinyl ethers 3 and o-quinone methides 2, thermally generated from 2-hydroxybenzyl alcohols 1, have been studied. The structure and conformational preferences of the 4-substituted 2-ethoxy-(2,3)-dihydro-2H-benzopyrans 4–9 obtained, which show new interesting features, are discussed together with competitive kinetic data. The cycloaddition process is concerted and involves o-quinone methides in the E-configuration
A chiral cyclohexane having two diarylethene chromophores was synthesized in an attempt to construct a molecule which shows a large optical rotation change by photoirradiation. Circular dichroism (CD) and optical rotation were found to change dramatically upon photoirradiation.