The Dakin-West Reaction of N-Alkoxycarbonyl-N-alkyl-.ALPHA.-amino Acids Employing Trifluoroacetic Anhydride.
作者:Masami KAWASE、Michitaka HIRABAYASHI、Hiroko KUMAKURA、Setsuo SAITO、Katsumi YAMAMOTO
DOI:10.1248/cpb.48.114
日期:——
Dakin-West reaction of N-alkoxycarbonyl-N-alkyl-alpha-amino acids (1a-j) with trifluoroacetic anhydride in the presence of pyridine gave alpha-amido trifluoromethyl ketones (2a-j), in which probable intermediates were mesoionic 1,3-oxazolium-5-olates (munchnones). The diastereoselective reduction of 2a-f with NaBH4 gave the threo-aminoalcohols (5a-f), which may be explained by the Felkin-Anh model. This was
在吡啶存在下,N-烷氧基羰基-N-烷基-α-氨基酸(1a-j)与三氟乙酸酐的Dakin-West反应得到α-酰胺基三氟甲基酮(2a-j),其中可能的中间体是介离子的1 ,3-恶唑-5-油酸酯(munchnones)。用NaBH4进行2a-f的非对映选择性还原得到了苏氨基氨基醇(5a-f),这可以用Felkin-Anh模型来解释。通过以高收率将5a-f转化为反式-5-三氟甲基-2-恶唑烷酮(6a-f)证实了这一点。