Palladium Catalyzed Additions to Allylic Hydroxy Phosphonates: Applications in the Enantioselective Synthesis of Enterolactone and Turmerone

Reaction of nonracemic allylic hydroxy phosphonates, prepared by the asymmetric phosphonylation of unsaturated aldehydes, with methyl chloroformate in pyridine yields the corresponding carbonates. The carbonates are excellent substrates for the palladium-catalyzed addition of nucleophiles. Addition of the nucleophile is highly regioselective, resulting in n -substituted vinyl phosphonates. The reaction of the allylic carbonates with aryl stannanes and malonates has been investigated. Progress in the application of these reactions to the synthesis of turmerone and enterolactone is reported.