Palladium-catalyzed trans-selective alkynylation–alkylation tandem process for the synthesis of (E)-3-alkyl-1-trialkylsilyl-3-alken-1-ynes
作者:Ei-ichi Negishi、Ji-cheng Shi、Xingzhong Zeng
DOI:10.1016/j.tet.2005.07.100
日期:2005.10
The Pd-catalyzed trans-selective monoalkynylation of 1,1-dihalo-l-alkenes with XZnC CSiMe3, where X is Br or Cl, can proceed generally in excellent yields in the presence of Pd(DPEphos)Cl-2 or Pd(dppf)Cl-2, and subsequent alkylation with methyl- and ethylzincs can proceed in excellent yields with >= 98% retention of configuration in the presence of Pd((BU3P)-B-t)(2) as a catalyst. (c) 2005 Elsevier Ltd. All rights reserved.
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
A simple synthesis of tetraethynylethenes and representative molecular structures of some dicobalt derivatives
作者:Olivia F Koentjoro、Philipp Zuber、Horst Puschmann、Andres E Goeta、Judith A.K Howard、Paul J Low
DOI:10.1016/s0022-328x(02)02191-5
日期:2003.3
6-bis(trimethylsilyl)-3,4-bis(trimethylsilylethynyl)-hex-3-ene-1,5-diyne with [Co2(CO)6(L2)] [L2=(CO)2 or μ-dppm] affords complexes in which one or two (trans) acetylene moieties are coordinated by a dicobalt fragment.
在回流的三乙胺中,钯-铜催化四氯乙烯与末端乙炔RCCH(R = SiMe 3,C 6 H 5,C 6 H 4 CN-4)的交叉偶联反应,可以分离出30-60%的产率得到相应的四乙炔基。1,6-双(三甲基甲硅烷基)-3,4-双(三甲基甲硅烷基乙炔基)-己-3-烯-1,5-二炔与[Co 2(CO)6(L 2)] [L 2 =( (CO)2或μ-dppm]提供了一种复合物,其中一个或两个(反式)乙炔部分由二叶草片段配位。