An Asymmetric, Bifunctional Catalytic Approach to Non-Natural α-Amino Acid Derivatives
作者:Daniel H. Paull、Ethan Alden-Danforth、Jamison Wolfer、Cajetan Dogo-Isonagie、Ciby J. Abraham、Thomas Lectka
DOI:10.1021/jo070472x
日期:2007.7.1
A catalytic, asymmetric process for the synthesis of 1,4-benzoxazinones from o-benzoquinone imides and ketene enolates is reported. Addition of Lewis acids (Zn(OTf)2, In(OTf)3, and in particular Sc(OTf)3) creates a bifunctional catalytic system that dramatically increases the reaction rate and the yield of these non-natural amino acid precursors while preserving the remarkable enantioselectivity inherent