Highly Enantioselective Synthesis of 3-Substituted Furanones by Palladium-Catalyzed Kinetic Resolution of Unsymmetrical Allyl Acetates

The Pd-catalyzed asymmetric allylic alkylation (AAA) holds a prominent position among the most versatile methods for C (cid:2) C bond formation that are widely applied in natural product synthesis. [1] This transformation typically features broad functional group tolerance and excellent regio-and enantioselectivity. [2] In particular, Pd-catalyzed kinetic resolutions [3,4] of symmetrical allylic substrates and dynamic kinetic transformations [5] have been developed recently, which extends their potential in synthetic chemistry. However, Pd-catalyzed kinetic resolutions of unsymmetrical acyclic allylic substrates with high yield and enantioselectivity are rare. [6] Furthermore, the enantioselective allylic alkylation of silyl enol ethers is still a challenging reaction. [7] Graening and Hartwig reported a highly enantioselective alkylation of monosubstituted allylic substrates with silyl enol ethers catalyzed by an Ir complex. [8] Although excellent results of allylic alkylations have been reported with enolates that are preformed or generated in situ, [9] to the best of our knowledge, Pd-catalyzed AAA with a nonstabilized silyl enol ether as nucleophile remains an elusive goal (Scheme 1). [10] Herein, we present the Pd-catalyzed kinetic resolution of 1,3-disubstituted unsymmetrical allylic substrates with non-stabilized silyl enol ethers as nucleophiles, which provides a highly regio-and enantioselective synthesis of 3-substituted g -butenolides