A Direct Synthesis of Allenes by a Traceless Petasis Reaction
Devon A. Mundal, Kelly E. Lutz and Regan J. Thomson*
*Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States, Email: r-thomsonnorthwestern.edu
D. A. Mundal, K. E. Lutz, R. J. Thomson, J. Am. Chem. Soc., 2012, 134, 5782-5785.
DOI: 10.1021/ja301489n (free Supporting Information)
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A one-pot synthesis of allenes by the 2-nitrobenzenesulfonylhydrazide-mediated coupling of hydroxyaldehydes or ketones with alkynyl trifluoroborate salts involves in situ formation of a sulfonylhydrazone that reacts with alkynyl trifluoroborates to generate a transient propargylic hydrazide species. Decomposition of this unstable hydrazide via an intermediate monoalkyldiazine produces the allene products.
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proposed reaction pathway
Y. Jiang, A. B. Diagne, R. J. Thomson, S. E. Schaus, J. Am. Chem. Soc., 2017, 139, 1826-1829.