Radical Germylzincation of α-Heteroatom-Substituted Alkynes.
J Am Chem Soc
; 140(50): 17632-17642, 2018 12 19.
Article
em En
| MEDLINE
| ID: mdl-30495946
ABSTRACT
The regio- and stereoselective addition of germanium and zinc across the C-C triple bond of nitrogen-, sulfur-, oxygen-, and phosphorus-substituted terminal and internal alkynes is achieved by reaction with a combination of R3GeH and Et2Zn. Diagnostic experiments support a radical-chain mechanism and the ß-zincated vinylgermanes that show exceptional stability are characterized by NMR spectroscopy and X-ray crystallography. The unique feature of this new radical germylzincation reaction is that the C(sp2)-Zn bond formed remains available for subsequent in situ Cu(I)- or Pd(0)-mediated C-C or C-heteroatom bond formation with retention of the double bond geometry. These protocols offer modular access to elaborated tri- and tetrasubstituted vinylgermanes decorated with heteroatom substituents ß to germanium that are useful for the preparation of stereodefined alkenes.
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MEDLINE
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Guideline
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article