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Synfacts 2008(1): 0020-0020  
DOI: 10.1055/s-2007-991468
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

One-Pot Synthesis of 2,3-Disubstituted Thiophenes via a [1,4]-Silyl Migration Reaction

Contributor(s): Victor Snieckus, Johnathan Board
N. O. Devarie-Baez, B. J. Shuhler, H. Wang, M. Xian*
Washington State University, Pullman, USA
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Publication History

Publication Date:
18 December 2007 (online)

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Significance

Described is a one-pot synthesis of 2,3-disubstituted thiophenes from 3-bromo-2-silyl-thiophenes. After lithium-halogen exchange and quenching with an aldehyde, the generated alkoxide intermediate undergoes a [1,4]-silyl migration to oxygen generating a C2-anion which, upon quenching with an electrophile, leads to the 2,3-disubstituted thiophene product. The migration reaction is presumably driven by strong Si-O bond formation and stability of the 2-anion. DMPU was necessary for silyl migration to occur; other additives (HMPA, TMEDA) were unsuccessful. The size of the silyl group appears not to have any effect upon the reaction.