Synthesis of Novel Chiral (Thio)ureas and Their Application as Organocatalysts and Ligands in Asymmetric Synthesis
作者:Marcos Hernández-Rodríguez、Claudia Gabriela Avila-Ortiz、Jorge M. del Campo、Delia Hernández-Romero、María J. Rosales-Hoz、Eusebio Juaristi
DOI:10.1071/ch08116
日期:——
The synthesis of novel chiral (thio)ureas 1–10 and 14–26 is described. These (thio)ureas incorporate chiral auxiliaries derived from (R)- or (S)-α-phenylethylamine, (R)-phenylglycine, or (1R,2S)-ephedrine. The phenylethyl group in compounds 1–10 and 21–24 adopts a particular orientation in the molecular structure as a consequence of 1,3-allylic strain with the (thio)carbonyl group. Ureas 1–10 were
描述了新型手性(硫)脲 1-10 和 14-26 的合成。这些(硫代)脲包含衍生自 (R)-或 (S)-α-苯乙胺、(R)-苯基甘氨酸或 (1R,2S)-麻黄碱的手性助剂。化合物 1-10 和 21-24 中的苯乙基在分子结构中采用特定的取向,这是由于 1,3-烯丙基应变与(硫代)羰基的结果。脲 1-10 作为路易斯碱性有机催化剂在环氧化物开环和醛缩合中进行了测试,发现四取代脲 (R,R)-2 在反应收率方面提供了最好的结果。(硫代)脲 20-26 作为对映选择性二乙基锌加成苯甲醛的配体进行了检测,观察到 C2 对称手性脲 (R,S,R,S)-20 以接近定量的产率和高达 62 的产率提供了预期的甲醇%对映体过量。