Shunying Liu
East China Normal University, China
Title: Enantioselective trapping of oxonium ylide with n-benzhydryl-α-imino ester: A rapid access to synthesis of β-tetrasubstituted α-amino acids
Biography
Biography: Shunying Liu
Abstract
β-Alkoxy Cβ-tetrasubstituted α-amino acid derivatives are commonly serviceable structural motifs in biologically active natural products and pharmaceuticals. Several efficient methods have been established to construct β-tetrasubstituted α-amino acids. Nevertheless, a rapid access to construction of these complex molecules from simple starting materials under mild conditions are urgently in demand. Multi-component reactions (MCRs) have provided such an approach to realize this goal. Here, a synergistic rhodium(II)/phosphoric acid catalyzed three component reaction of 3-diazooxindoles, alcohols and N-benzhydryl-α-imino ester is successfully developed to provide an efficient strategy for the rapid construction of chiral β-alkoxy Cβ-tetrasubstituted α-amino acid derivatives with high diastereoselectivity (up to 20:1 dr) and excellent enantioselectivity (up to 98:2 er) from simple starting points under mild conditions (Scheme 1). The resulting multi-component products 4 readily afforded 3-spirocyclic oxindole 5 under the standard hydrogenation conditions followed a cyclization with CSCl2 in a good yield remaining excellent enantioselectivity.