ChemInform Abstract: Asymmetric Synthesis of 4-Alkoxy-4-alkylcyclohexen-2-ones. Application Toward the Synthesis of (+)-Abscisic Acid.

ChemInform Abstract

The bicyclic lactam (I) is converted to the keto lactam (IV) via the thioacetal (III). (IV) reacts with the Grignard compounds (V) to give the alcohols (VI) and (VII) as a mixture of diastereomers. This is transformed into a mixture of the corresponding benzyl derivatives (IX) and (X) which are separated by means of chromatography. The endo-isomers (IXa) and (IXb) are submitted to subsequent reactions, forming the cyclohexenone derivatives (XI) and (XIII) respectively, as outlined in the reaction scheme. The compound (XIIIc) is transformed into the derivative (-)-(XVI) which serves as a model compound for the synthesis of (+)-abscisic acid (XVII).