作者:M. Pallavicini、E. Valoti、L. Villa、I. Resta
DOI:10.1016/s0957-4166(00)86207-2
日期:1994.3
A new synthesis of (−)-esermethole, based on the asymmetric alkylation at C(3) of racemic 1,3-dimethyl-5-methoxyoxindole (3), is described. The chloroacetyl derivatives of (−)-menthol and (S)-N-methyl-(1-phenylethyl) amine were chosen as chiral alkylating agents and used under different reaction conditions (temperature, solvent and base). In particular, the latter reacted with 3 in toluene at 10°C
( - ) -的一种新的合成esermethole,基于所述不对称烷基化在外消旋1,3-二甲基-5- methoxyoxindole(的C(3)3),进行说明。选择(-)-薄荷醇和(S)-N-甲基-(1-苯乙基)胺的氯乙酰基衍生物作为手性烷基化剂,并在不同的反应条件(温度,溶剂和碱)下使用。尤其是,后者在叔丁基锂的存在下于10°C在甲苯中与3反应,得到(3S,1'S)-N-甲基-N-(1'-苯乙基)-1,3-二甲基具有63%de的-5-甲氧基氧吲哚-3-ilacetamide(10)。该中间体容易地与不期望的次要(3R,1'S)非对映异构体(11)分离,并在两个步骤中转化为(-)-乙二咪唑(99.6%ee)。