Diastereoselective Synthesis of γ-Substituted 2-Butenolides via (CDC)-Rh-Catalyzed Intermolecular Hydroalkylation of Dienes with Silyloxyfurans.

Catalytic intermolecular hydroalkylation of dienes with silyloxyfuran nucleophiles is reported. Reactions are catalyzed by 5 mol % of a (CDC)-Rh complex and proceed in up to 87% yield and 6:1 dr (syn/anti) to provide allylic butenolides bearing vicinal stereocenters. Reactions proceed with terminal aryl and alkyl dienes and with modified silyl enol ether nucleophiles including a thiophenone variant. Utility of the products is demonstrated in the synthesis of a polypropionate anti,syn-stereotriad.