Reactive-state spin-dependent diastereoselective photoisomerization of trans,trans-2,3-diphenylcyclopropane-1- carboxylic acid derivatives included in zeolites

The asymmetric induction facilitated by a chiral auxiliary during the photoisomerization of trans,trans-2,3-diphenylcyclopropane derivatives depends on the medium (solution vs zeolite) and the reactive state (singlet vs triplet). Within zeolites, direct excitation most likely proceeds via a zwitterionic intermediate, while triplet sensitization most likely proceeds via a diradical intermediate