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DOI: 10.1055/s-2007-968738
Stereoselectivity in Cross-Coupling of α-Bromo Sulfoxides and Arylboronic Acids
Contributor(s):Paul Knochel, Andrei GavryushinUniversidad de Valencia, Spain
Palladium-Catalyzed Suzuki-Miyaura Reaction Involving a Secondary sp3 Carbon: Studies of Stereochemistry and Scope of the Reaction
Chem. Eur. J. 2007, 13: 4223-4229
Publication History
Publication Date:
24 July 2007 (online)
Key words
Suzuki-Miyaura coupling - bromo sulfoxides - palladium
Significance
This is the first report concerning a mechanistic study of still rather uncommon Csp 3-Csp 2 cross-coupling reactions. The whole process was shown to proceed with inversion of the configuration, which takes place on the palladium oxidative addition step. Since enantiopure aryl sulfoxides are readily available, this method has also a significant synthetic utility for the preparation of various chiral target molecules.
Comment
Bromination of a sulfoxide with Br2-AgNO3 gives almost a single diastereomer of the product (95% de). Interestingly, the cross-coupling of the opposite diastereomer under the described conditions is much slower. The starting sulfoxides are easy to prepare enantioselectively from chiral menthyl sulfinate and organometallic reagents (see, for instance: T. Sato, T. Ohara, Y. Ueda, K. Yamakawa J. Org. Chem. 1989, 54, 3130).