Construction of Quaternary Stereogenic Centers via [2 + 2] Cycloaddition Reactions. Synthesis of Homochiral 4,4-Disubstituted 2-Azetidinones and Imine Substituent Effects on β-Lactam Formation
作者:Claudio Palomo、Jesus M. Aizpurua、Jesus M. García、Regina Galarza、Marta Legido、Raquel Urchegui、Pascual Román、Antonio Luque、Juan Server-Carrió、Anthony Linden
DOI:10.1021/jo962017z
日期:1997.4.1
A study on the asymmetric construction of quaternary stereogenic centers via [2 + 2] cycloaddition reaction of ketenes with ketimines is described. Reaction of achiral ketenes and chiral alpha-alkoxy ketone-derived imines resulted in formation of new beta-lactams as single diastereomers. The cycloaddition was extended to pyruvate imines, aralkyl ketone-derived imines, and dialkyl ketimines. In these
描述了通过烯酮与酮亚胺的[2 + 2]环加成反应对四元立体异构中心进行不对称构建的研究。非手性烯酮与手性α-烷氧基酮衍生的亚胺的反应导致形成新的β-内酰胺类单一非对映异构体。环加成反应扩展到丙酮酸亚胺,芳烷基酮衍生的亚胺和二烷基酮亚胺。在这些情况下,使用β-甲硅烷基链烷酮烯酮和Evans-Sjögren烯酮可以令人满意地实现不对称诱导。衍生自可烯醇化二烷基酮的C,C-双(三甲基甲硅烷基)甲胺酮亚胺干净地导致相应的C(4)二取代的β-内酰胺不去质子化。因此,提供了一种聚合的不对称合成β-内酰胺的通用方法,其中C(4)作为季碳存在。