作者:Hao-Ming Chang、Chien-Hong Cheng
DOI:10.1021/jo991651k
日期:2000.3.1
with aryl and vinylic halides to give diene products (3p-w). For 2d, both E and Z isomers 3t and 3u of the diene product were observed. For 2e, two regioisomers 3vand 3w were isolated with 3w likely from alkene isomerization of 3v. Various palladium systems were tested for the catalytic activity of diene formation. In addition to Pd(dba)(2)/PPh(3), Pd(OAc)(2)/PPh(3), PdCl(2)(PPh(3))(2), and PdCl(2)(dppe)
在N,N-二甲基乙酰胺(DMA)中,在Pd(dba)(2)(dba =二苄叉基丙酮)存在下,各种各样的芳基卤化物和乙烯基卤化物与1,1-二甲基烯丙基(2a)和碳酸钾反应在120摄氏度下得到相应的二烯CH(2)C(CH(3))CRCH(2)(3a-o),其中R为芳基或乙烯基,收率很好。与相应的芳基碘化物和氯化物相比,芳基溴化物可获得更高的二烯产物收率。在相似的反应条件下,四甲基丙烯(2b),1-甲基-1-苯基丙烯(2c),1-甲基-3-苯基丙烯(2d)和1-环己基烯丙烯(2e)也与芳基和乙烯基卤化物反应生成二烯产物(3p-w)。对于2d,观察到二烯产物的E和Z异构体3t和3u。对于2e,分离了两个区域异构体3vand 3w,其中3w可能来自3v的烯烃异构化。测试了各种钯体系对二烯形成的催化活性。除了Pd(dba)(2)/ PPh(3),Pd(OAc)(2)/ PPh(3),PdCl(2)(P