Highly Diastereoselective Arylation of (<i>S</i>)-Mandelic Acid Enolate: Enantioselective Synthesis of Substituted (<i>R</i>)-3-Hydroxy-3-phenyloxindoles and (<i>R</i>)-Benzylic Acids and Synthesis of Nitrobenzophenones
作者:Santiago Barroso、Gonzalo Blay、Luz Cardona、Isabel Fernández、Begoña García、José R. Pedro
DOI:10.1021/jo0402069
日期:2004.10.1
leads directly to enantiomerically pure (R)-3-hydroxy-3-phenyloxindoles. On the other hand the basic hydrolysis of the dioxolanone moiety in all the arylation products (ortho and para) leads to enantiomerically pure substituted (R)-benzylic acids. The oxidative decarboxylation of these latter with oxygen as terminal oxidant in the presence of pivalaldehyde and the Co(III)-Me2opba complex as catalyst gives
描述了容易获得的取代的(R)-3-羟基-3-苯基氧吲哚,(R)-苯甲酸和二苯甲酮。衍生自旋光性(S)-扁桃酸和新戊醛的(2 S,5 S)-顺式-1,3-二氧戊环-4-一的烯醇锂与数个邻卤和对卤硝基苯的反应易于进行得到具有良好收率和非对映选择性的相应芳基化产物。邻位用Zn / HCl / EtOH还原硝基-硝基芳基化产物与二氧戊环部分的分子内氨基分解反应直接导致对映体纯的(R)-3-羟基-3-苯基氧吲哚。另一方面,所有芳基化产物(正和对位)中二氧戊环酮部分的碱性水解导致对映体纯的取代的(R)-苯甲酸。在新戊醛和Co(III)-Me 2 opba络合物作为催化剂的存在下,用氧作为末端氧化剂,将后者氧化脱羧,得到取代的硝基二苯甲酮。