Synthesis of optically active .ALPHA.-alkyl or .ALPHA.-aryl acids from L-.ALPHA.-amino acids by the use of organocopper reagents.
作者:SHIRO TERASHIMA、CHUNGCHYI TSENG、KENJI KOGA
DOI:10.1248/cpb.27.747
日期:——
With an aim to further explore the utility of L-α-amino acids (I) in the synthesis of optically active compounds, the reaction of optically active α-tosyloxy acids and their derivatives (III) readily obtainable from I, with several types of organocopper reagents were studied. Although there still remain some ambiguity in the formation of unusual reaction products such as the β-keto ester (dl-6) and the vicinal diol ((R)(+)-13) and in lower yields for the substitution products, it has become evident that when optically active α-tosyloxy acids prepared from L-phenylalanine, L-alanine, and L-leucine, respectively, are treated with lithium dialkyl- or diarylcuprates, the substitution reactions can proceed with almost full inversion to give corresponding optically active α-alkyl or α-aryl acids in max. 63% yield.
为了进一步探索L-α-氨基酸(I)在光学活性化合物合成中的用途,由I容易获得光学活性α-甲苯磺酰氧基酸及其衍生物(III)与几种类型的反应研究了有机铜试剂。尽管在形成不寻常的反应产物(如 β-酮酯 (dl-6) 和邻二醇 ((R)(+)-13))以及取代产物的产率较低方面仍然存在一些模糊性,但它已经很明显,当分别由L-苯丙氨酸、L-丙氨酸和L-亮氨酸制备的光学活性α-甲苯磺酰氧基酸用二烷基铜或二芳基铜酸锂处理时,取代反应可以几乎完全反转进行,得到相应的光学活性最大 α-烷基或 α-芳基酸收率63%。