Stereoselective [2+2] photocycloaddition of acetylene to chiral 2(5H)-furanones

Abstract The photochemical [2+2] cycloaddition of acetylene to chiral 2(5 H )-furanones is investigated. The effect of the substituent at the stereogenic center of the lactone on the chemical yield and facial diastereoselectivity is evaluated. Using a C 2 -symmetric bis-lactone as substrate, a diastereomeric excess higher than 98% is found.