Alternative Synthesis of (Z)-1-Aryl-1-(tributylstannyl)-2-(triethylgermyl)ethenes and the Unprecedented Germyl 1,2-Migration during the Destannylation of the Adducts
Alternative Synthesis of (<i>Z</i>)-1-Aryl-1-(tributylstannyl)-2-(triethylgermyl)ethenes and the Unprecedented Germyl 1,2-Migration during the Destannylation of the Adducts
作者:Taichi Nakano、Yoshiya Senda、Takashi Miyamoto
DOI:10.1246/cl.2000.1408
日期:2000.12
A specific combination catalyst, Pd(dba)2 and 4-ethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane, effectively catalyzed the addition of tributyl(triethylgermyl)stannane to arylacetylenes in tetrahydrofuran to give (Z)-1-aryl-2-(germyl)-1-(stannyl)ethenes in high yields. The (Z)-1-aryl-2-(germyl)-1-(stannyl)ethenes were subject to the unprecedented germyl 1,2-migration during the destannylation using HI / TBAI in toluene to produce 1-aryl-1-(germyl)ethenes in high yields.
Synthesis of (Z)-1-aryl-2-(germyl)-1-(stannyl)ethenes and the related ethenes, precursors to stereodefined germylethenes, via Pd(dba)2–P(OCH2)3CEt-catalyzed germastannation of acetylenes in THF
(Z)-1-Aryl-2-(germyl)-1-(stannyl)ethenes are synthesized in high yields by the addition of tributyl(triethylgermyl)stannane to arylacetylenes catalyzed by a specific combination catalyst, Pd(dba)(2) and 4-ethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane, in tetrahydrofuran. Ethynylthiophene and 2-methyl-3-butyn-2-ol are also subject to the germastannation to afford the respective adducts in high yields. In addition, the J(Sn-H) and C-13-NMR data for their adducts are presented. (C) 2001 Elsevier Science B.V. All rights reserved.