Efforts Directed toward the Synthesis of Colchicine: Application of Palladium-Catalyzed Siloxane Cross-Coupling Methodology
作者:W. Michael Seganish、Christopher J. Handy、Philip DeShong
DOI:10.1021/jo051636h
日期:2005.10.1
Colchicine is an important and synthetically challenging natural product. The key synthetic step in this approach to the synthesis of colchicine involved a palladium-catalyzed cross-coupling reaction between 5-bromotropolone (4) and an aryl siloxane to form the aryl-tropolone bond. The coupling of a variety of highly functionalized aryl siloxane derivatives was investigated and optimized coupling conditions were developed. It was discovered that a palladium catalyst with a high degree of phosphine ligand coordination (5 equiv of phosphine/mol Pd) was necessary to efficiently couple aryl siloxanes with 5-bromotropolone (4). In addition, the coupling approach has provided a direct comparison between siloxane and boronic acid coupling technologies that demonstrated that aryl siloxanes and boronic acids produce similar yields of highly functionalized biaryl products.
Nair, Vijay; Powell, Dennis W.; Suri, Suresh Chander, Synthetic Communications, 1987, vol. 17, # 16, p. 1897 - 1900
作者:Nair, Vijay、Powell, Dennis W.、Suri, Suresh Chander
DOI:——
日期:——
BANWELL, MARTIN G.;CAMERON, JENNIFER M.;COLLIS, MAREE P.;CRISP, GEOFFREY +, AUSTRAL. J. CHEM., 44,(1991) N, C. 705-728
作者:BANWELL, MARTIN G.、CAMERON, JENNIFER M.、COLLIS, MAREE P.、CRISP, GEOFFREY +
DOI:——
日期:——
NAIR, VIJAY;POWELL, DENNIS W.;SURI, SURESH CHANDER, SYNTH. COMMUN., 17,(1987) N 16, 1897-1900
作者:NAIR, VIJAY、POWELL, DENNIS W.、SURI, SURESH CHANDER