Chiral α-and β-hydroxy acids such as (S)-lactic acid,(S)-phenyllactic acid,(S)-mandelic acid, or (3 R)-3-hydroxybutyric acid have been used as tether groups for intramolecular and diastereoselective [2+ 2] photocycloaddition of 3-oxocyclohexene carboxylic acid derivatives. Total regiocontrol toward the straight adduct and high diastereoselectivities (up to 94%) were observed in the case of butenyl lactate 11. After separation of the two ...
