Hydroxyacids as efficient chiral spacers for asymmetric intramolecular [2+2] photocycloadditions

Article abstract of DOI:10.1016/S0040-4039(96)02499-9

An indirect and efficient enantioselective [2+2] photocycloaddition between 3-carboxycyclohex-2-enone and allyl alcohol, involving a three step sequence, is described. When the reagents are linked by covalent bonds to a chiral spacer such as L-lactic or (R)-3-hydroxybutyric acids, the corresponding photocycloadducts are isolated in high yields, with very high regio and diastereoselectivities. The reaction affords polyfunctional cyclobutanes as pure enantiomers.