[摘要]：Catalytic and highly enantioselective Diels-Alder reaction of cyclic and provides cyclic a-quaternary a-amino acid precursors, e.g. II (R = Me, Ph). The conformationally flexible chiral ammonium salt of H-L-Phe-L-Leu-N(CH2CH2)2-reduced triamine with pentafluorobenzenesulfonic acid is very effective as an asym. catalyst for the Diels-Alder reaction.
