Development of Chemo- and Enantioselective Palladium-Catalyzed Decarboxylative Asymmetric Allylic Alkylation of α-Nitroesters

Abstract

We describe the development of a Pd-catalyzed decarboxylative asymmetric allylic alkylation of α-nitro allyl esters to afford acyclic tetrasubstituted nitroalkanes. Optimization of the reaction parameters revealed unique ligand and solvent combinations crucial for achieving chemo- and enantioselective C-alkylation of electronically challenging benzylic nitronates and sterically encumbered 2-allyl esters. Substrates were efficiently accessed in a combinatorial fashion by a cross-Claisen/ α-arylation sequence. The method provides functional group orthogonality that complements nucleophilic imine allylation strategies for α-tertiary amine synthesis.

Keywords: allylic alkylation; asymmetric catalysis; chemoselectivity; enantioselectivity; palladium catalysis.