Rhodium-Catalyzed Highly Enantio- and Diastereoselective Alkenylation of β,γ-Unsaturated Butenolides via Dynamic Kinetic Resolution

A rhodium-catalyzed highly enantio- and diaster-eoselective alkenylation of Ay-unsaturated butenolides is reported. The use of a chiral diene ligand, (S,S)-Ph-bod, enables the facile synthesis of chiral butyrolactones in high yields with extremely high enantioselectivities (>99% ee in all cases) and high diastereoselectivities (up to >20:1 dr). The key process of the reaction involves the isomerization of beta,gamma-unsaturated butenolides to racemic alpha,beta-unsaturated butenolides and the subsequent dynamic kinetic resolution through ligand-controlled, enantio-selective alkenylation with an alkenylrhodium species that is generated in situ via 1,4-rhodium migration.

Automated summary

A rhodium-catalyzed highly enantio- and diaster-eoselective alkenylation reaction of Ay-unsaturated butenolides is reported. The use of a chiral diene ligand enables the synthesis of chiral butyrolactones in high yields with extremely high enantioselectivities and high diastereoselectivities. The key process involves the isomerization of butenolides and subsequent dynamic kinetic resolution.