Asymmetric synthesis of orthogonally protected trans-cyclopropane γ-amino acids via intramolecular ring closure
作者:David J. Fox、Daniel Sejer Pedersen、Stuart Warren
DOI:10.1039/b606879k
日期:——
enantiomerically-enriched trans-cyclopropane amino- and hydroxy-acids can be achieved by intramolecular ring closure in moderate to good yields. The optically active cyclopropane precursors are easily prepared in a short sequence from inexpensive, commercially available olefins and tert-butyl acetate. Several leaving groups and bases were compared for the cyclopropanation step, showing that the diphenylphosphinate and
对映体富集的反式环丙烷氨基和羟基酸的合成可以通过分子内闭环以中等至良好的产率实现。旋光性环丙烷前体可容易地以短序列由廉价的可商购的烯烃和乙酸叔丁酯制备。比较了环丙烷化步骤中的几个离去基团和碱基,表明当与LDA或NaHMDS组合使用时,二苯基次膦酸酯和甲苯磺酰基离去基团可提供最佳结果。