A New and Convenient Chiral Auxiliary for Asymmetric Diels-Alder Cycloadditions in Environmentally Benign Solvents
作者:Frederick J. Lakner、George R. Negrete
DOI:10.1055/s-2002-22712
日期:——
investigations of asymmetric Diels-Alder reactions using a new chiral auxiliary are presented. The auxiliary is readily prepared from an aldehyde and asparagine in water. The resulting heterocycle is coupled with acryloyl chloride in the same pot to provide chiral dienophiles. These are reacted with cyclopentadiene at room temperature in water or ethanol-water to provide cycloaddition adducts diastereoselectively
介绍了使用新手性助剂对不对称 Diels-Alder 反应的初步研究。助剂很容易由醛和天冬酰胺在水中制备。所得杂环在同一锅中与丙烯酰氯偶联以提供手性亲二烯体。它们在室温下在水或乙醇-水中与环戊二烯反应,以非对映选择性提供环加成加合物,如皂化产物 5-降冰片烯-2-羧酸的手性 HPLC 所证明的(内异构体的 ee 为 47-64%;内/外82:18)。