Highly Selective Synthesis of (<i>E</i>)-3-Methyl-1-trialkylsilyl-3-en-1-ynes via <i>trans</i>-Selective Alkynylation Catalyzed by Cl<sub>2</sub>Pd(DPEphos) and Stereospecific Methylation with Methylzincs Catalyzed by Pd(<i><sup>t</sup></i>Bu<sub>3</sub>P)<sub>2</sub>
作者:Ji-cheng Shi、Xingzhong Zeng、Ei-ichi Negishi
DOI:10.1021/ol030017x
日期:2003.5.1
[reaction: see text] trans-Selective (>or=98%) monoalkynylation of 1,1-dibromo-1-alkenes and 1,1-dichloro-1-alkenes catalyzed by Cl(2)Pd(DPEphos) followed by stereospecific methylation with Me(2)Zn or MeZnX (X= Cl or Br) catalyzed by Pd((t)()Bu(3)P)(2) provides an efficient and stereoselective (>or=98%) route to 5, convertible to a wide variety of enynes and conjugated dienes. In the cases of 1,1-dibromo-1-alkenes
[反应:见正文]由Cl(2)Pd(DPEphos)催化的立体选择性催化的1,1-二溴-1-烯烃和1,1-二氯-1-烯烃的反式选择性(>或= 98%)单烷基化由Pd((t)()Bu(3)P)(2)催化的Me(2)Zn或MeZnX(X = Cl或Br)甲基化可提供有效且立体选择性的途径(>或= 98%)生成5,可转换为多种烯炔和共轭二烯。在1,1-二溴-1-链烯的情况下,Sonogashira炔基化也可能是令人满意的,但是在使用1,1-二氯-1-链烯的情况下,它明显不如炔基锌反应令人满意。