Efforts directed toward the synthesis of colchicine: application of palladium-catalyzed siloxane cross-coupling methodology.
J Org Chem
; 70(22): 8948-55, 2005 Oct 28.
Article
en En
| MEDLINE
| ID: mdl-16238332
ABSTRACT
[reaction see text] 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.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Paladio
/
Siloxanos
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Colchicina
/
Reactivos de Enlaces Cruzados
Idioma:
En
Revista:
J Org Chem
Año:
2005
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
EEUU
/
ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
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EUA
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UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA