Enantioselective Synthesis of Allenes by Catalytic Traceless Petasis Reactions
Yao Jiang, Abdallah B. Diagne, Regan J. Thomson* and Scott E. Schaus*
*Department of Chemistry, Northwestern University, Evanston,
Illinois 60208; Department of Chemistry, Boston University, Boston,
Massachusetts 02215, United States, Email: r-thomson
northwestern.edu,
seschausbu.edu
Y. Jiang, A. B. Diagne, R. J. Thomson, S. E. Schaus, J. Am. Chem. Soc., 2017, 139, 1826-1829.
DOI: 10.1021/jacs.6b11937
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Abstract
An asymmetric boronate addition to sulfonyl hydrazones catalyzed by chiral biphenols provides enantioenriched allenes in a traceless Petasis reaction. The resulting Mannich product from nucleophilic addition eliminates sulfinic acid, yielding a propargylic diazene that performs an alkyne walk to afford the allene. Two enantioselective approaches have been developed for the synthesis of allylic hydroxyl allenes and 1,3-alkenyl allenes.
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Development of an enantioselective allene synthesis reaction. Asymmetric routes to chiral allenes from (A) alkynyl boronate addition to glycolaldehyde imine and (B) allylation of alkynyl hydrazones.
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A Direct Synthesis of Allenes by a Traceless Petasis Reaction
D. A. Mundal, K. E. Lutz, R. J. Thomson, J. Am. Chem. Soc., 2012, 134, 5782-5785.
Key Words
Petasis Reaction, allenes, 1,4-dienes
ID: J48-Y2017
