Chiral alpha- and beta-hydroxy acids such as (S)-lactic acid, (S)-phenyllactic acid, (S)-mandelic acid, or (3R)-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
Application of chiral tethers to intramolecular [2+2] photocycloadditions: synthetic approach to (−)-italicene and (+)-isoitalicene
作者:Sophie Faure、Olivier Piva
DOI:10.1016/s0040-4039(00)01933-x
日期:2001.1
A synthetic approach to (−)-italicene and (+)-isoitalicene, sesquiterpenes which possess the rare tricyclo[5.4.0.01,5] undecane skeleton has been developed using as key step a highly regio- and diastereoselective [2+2] photocycloaddition. (S)-Lactic acid plays the role of a chiral removable tether group during the building of the cyclobutane ring.