Regioselective [2 + 2]-photocycloaddition reactions of chiral tetronates—influence of temperature, pressure, and reaction mediumThis paper is dedicated to Professor Rolf Gleiter (Heidelberg) on the occasion of his 70th birthday.

The intramolecular [2 + 2]-photocycloaddition of the 1,3-divinyl-2-cyclopentyl tetronates 1 was performed under various conditions to give perfect diastereoselectivity and a regioselectivity of up to 85/15 in the presence of γ-cyclodextrin by differentiating the two chemically very similar double bonds of 1. [ABSTRACT FROM AUTHOR]