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DOI: 10.1055/s-2008-1078621
Fe-Catalyzed Cross-Coupling of Dienol Phosphates with Grignard Reagents
Contributor(s):Paul Knochel, Andrey GavryushinUniversité Cergy-Pontoise, France
Efficient Preparation of Terminal Conjugated Dienes by Coupling of Dienol Phosphates with Grignard Reagents under iron Catalysis
Org. Lett. 2008, 10: 2389-2392
Publication History
Publication Date:
22 August 2008 (online)
Key words
terminal dienes - dienol phosphates - iron catalysis - Grignard reagents
Significance
Iron-catalyzed cross-coupling reactions have recently attracted a great amount of attention of synthetic chemists. Herein, the authors elegantly used dienol phosphates instead of poorly stable dienyl halides as electrophiles for a simple and general Fe-catalyzed cross-coupling reaction with Grignard reagents. The reaction with alkylmagnesium salts proceeds stereoselectively and in high yields. This methodology is illustrated by a synthesis of Diparopis castanea pheromone.
Comment
Dienol diethylphosphates are easily prepared from the corresponding enals or enones. The cross-coupling with aryl Grignard proceeds in lower yields (a single example given). Secondary alkyl Grignards react seemingly as smooth as the primary analogues. While Fe-catalyzed coupling of alkenyl halides and Grignard reagents proceeds is strongly promoted by NMP (G. Cahiez, H. Avedissian Synthesis 1998, 1199), in this reaction NMP is deleterious.