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Synfacts 2008(2): 0136-0136  
DOI: 10.1055/s-2007-992466
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

Rh-Catalyzed Synthesis of 3-Alkylideneoxindoles from 2-Alkynylisocyanates and Arylboronic Acids

Contributor(s): Victor Snieckus, Jignesh J. Patel
T. Miura, Y. Takahashi, M. Murakami*
Kyoto University, Japan
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Publication History

Publication Date:
23 January 2008 (online)

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Significance

Reported is a stereoselective rhodium-catalyzed reaction of 2-alkynylaryl isocyanates with aryl and alkenyl boronic acids which leads to 3-alkylideneoxindoles. The reaction proceeds via rhodium/boron transmetallation to generate organorhodium(I) species D followed by carborhodation of alkynes and isocyanates to give E. The method represents a new regioselective transfer of aryl and heteroaryl entities from boron to the alkyne moiety in an overall two C-C bond-forming process. In the proposed mechanism, three possible intermediates (F, G and H) are proposed for the transformation of E to I.