An efficient and convenient two step synthesis of each of the four possible diastereoisomers of the N-terminal amino acid component of nikkomycins is described. We first synthesized α-amino-β-oxo acids by aminoalkylation of ketones with iminium salts. The second step using Pearlman’s catalyst gave directly nonnatural and natural precursors 13 - 16 of nikkomycins 1 which were easily separated by chromatography on silica gel.
本文描述了尼科霉素N-末端氨基酸组分的四个可能的对映异构体的高效便捷的两步合成方法。我们首先通过氨基烷基化酮与亚胺盐合成α-氨基-β-酮酸。第二步使用Pearlman的催化剂直接得到尼科霉素1的非天然和天然前体13-16,这些前体可以通过硅胶色谱轻松分离。