Catalytic Asymmetric Ring-Opening of σ-Symmetric Cyclic Carbonates with Chiral Amino Sulfonamide Catalysts

Abstract

Enantioselective ring-opening of σ-symmetric six-membered cyclic carbonates with benzyl alcohol catalyzed by 20 mol% of chiral amino sulfonamide catalysts afforded chiral acyclic carbonates in up to 79% ee.Catalytic asymmetric desymmetrization is a general and convenient strategy for asymmetric synthesis. [1][2][3][4][5][6][7] We have developed several enzymatic or nonenzymatic catalytic asymmetric desymmetrizations of σ-symmetric compounds, such as 1,3-diesters, 8-10 cyclic anhydrides, 11-13 1,3-diols, 10,14-17 and cyclic carbonates. 18 In the desymmetrization of σ-symmetric six-membered cyclic carbonate 1a, a catalytic amount of BINOL-based phosphoric acid 2 was used as a chiral Brønsted acid catalyst. As a result, asymmetric ring-opening of 1a with 2 afforded the acyclic carbonate (S)-3a in 94% yield with 81% ee as shown in Scheme 1. 19