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DOI: 10.1055/s-0030-1259387
Palladium-Catalyzed Heterannulation Synthesis of 3-Borylated Indoles
J. Huang, S. J. F. Macdonald, J. P. A. Harrity*
University of Sheffield and GlaxoSmithKline, Stevenage, UK
Publication History
Publication Date:
19 January 2011 (online)

Significance
Reported is the synthesis of indole-3-boropinacolates 2 via a palladium-catalyzed borylative cyclization of 2-alkynylanilines 1. N-Sulfonyl anilines (R³ = SO2R) were found to be suitable substrates, although N-Boc and N-benzyl anilines failed. Alkyl and aryl alkynes were both well tolerated. The synthesis of 7-azaindole-3-boropinacolate 3 was also reported. A one-pot cyclization/Suzuki-Miyaura cross-coupling procedure delivered biaryl 4, a core fragment of the natural product fluvastatin. Further derivatization of indoles 2 was accomplished via copper-catalyzed azido deboronation to efficiently give 5, which was shown to undergo [3+2] cycloaddition to give 6 in excellent yields.