A Reinvestigation of the α-Alkylation of 4-Monosubstituted 2-phenyloxazol-5(4<i>H</i>)-ones (‘azlactones’): A general entry into highly functionalized α,α-disubstituted α-amino acids
作者:Daniel Obrecht、Udo Bohdal、Ruth Ruffieux、Klaus Müller
DOI:10.1002/hlca.19940770520
日期:1994.8.10
Novel, more reliable and general reaction conditions for the α-alkylation of 4-monosubstituted 2-phenyloxazol-5(4H)-ones ( = 4-monosubstituted 2-phenyl-azlactones) rac-2 to 4,4-disubstituted 2-phenyloxazol-5(4H)-ones rac-1 were found (Scheme 2). Thus, a whole range of highly functionalized rac-1 were prepared in medium-to-good overall yields (40-90%, see Table). Azlactones rac-1 are ideal precursors
4-单取代的2-苯基恶唑-5(4 H)-ones(= 4-单取代的2-苯基-氮杂内酯)rac - 2至4,4-二取代的2-的α-烷基化的新颖,更可靠,更通用的反应条件发现苯恶唑-5(4 H)-one rac - 1(方案2)。因此,以中等到良好的总收率(40-90%,见表)制备了一系列高度功能化的rac - 1。lac内酯rac - 1是合成光学纯α,α-二取代(R)和(S)的理想前体。)-α-氨基酸。