Highly diastereo- and enantioselective synthesis of syn-β-substituted tryptophans via asymmetric Michael addition of a chiral equivalent of nucleophilic glycine and sulfonylindoles

摘要

The asymmetric synthesis of syn-p-substituted tryptophan derivatives was carried out by the Michael addition of chiral equivalent of nucleophilic glycine with sulfonylindoles, and high diastereo- and enantioselectivities were achieved. The resulting adducts were readily converted to syn-p-substituted tryptophans in 96% yield, indicating that the proposed method is a highly efficient route to chiral syn-p-substituted tryptophans.