Racemic and Asymmetric Diels−Alder Reactions of 1-(2-Oxazolidinon-3-yl)-3-siloxy-1,3-butadienes
作者:Jacob M. Janey、Tetsuo Iwama、Sergey A. Kozmin、Viresh H. Rawal
DOI:10.1021/jo005619y
日期:2000.12.1
1-amino-3-siloxy dienes, the 1-(2-oxazolidinon-3-yl)-3-siloxy-1,3-butadienes are still very reactive in Diels-Alder reactions, somewhat more than 1,3-dialkoxy-1, 3-butadienes (e.g., Danishefsky's diene). The cycloadditions of the achiral and chiral dienes with several different dienophiles were examined. The reactions proceeded in good yield, with modest to high endo selectivity. The chiral dienes exhibited
从容易获得的起始原料制备非手性和手性的1-(2-恶唑烷酮-3-基)-3-甲硅烷氧基-1,3-丁二烯。虽然比母体1-氨基-3-甲硅烷氧基二烯更稳定,但1-(2-恶唑烷酮-3-基)-3-甲硅烷氧基-1,3-丁二烯在狄尔斯-阿尔德反应中仍然具有很高的反应性,比1,3-二烷氧基-1,3-丁二烯(例如,Danishefsky的二烯)。检查了具有几种不同的双亲性的非手性和手性二烯的环加成。反应以高产率进行,具有中等至高的内选择性。手性二烯在与α-取代的丙烯醛,马来酸酐和N-苯基马来酰亚胺的环加成中表现出优异的面部选择性。在环加合物还原和水解后,获得的ee范围为22%至> 98%的取代的环己酮。