Dual-Hydrogen-Bond Donor and Brønsted Acid Cocatalysis Enables Highly Enantioselective Protio-Semipinacol Rearrangement Reactions
Melanie A. S. Blackburn, Corin C. Wagen, M. Raul Bodrogean, Pamela M. Tadross, Andrew J. Bendelsmith, Dennis A. Kutateladze and Eric N. Jacobsen*
*Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States,
Email: jacobsen
chemistry.harvard.edu
M. A. S. Blackburn, C. C. Wagen, M. R. Bodrogean, P. M. Tadross, A. J. Bendelsmith, D. A. Kutateladze, E. N. Jacobsen, J. Am. Chem. Soc., 2023, 145, 15036-15042.
DOI: 10.1021/jacs.3c02960
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Abstract
A catalytic protio-semipinacol ring-expansion reaction for the highly enantioselective conversion of tertiary vinylic cyclopropyl alcohols into cyclobutanone products bearing α-quaternary stereogenic centers relies on the cocatalytic effect of a chiral dual-hydrogen-bond donor (HBD) with hydrogen chloride. In a stepwise mechanism, protonation of the alkene is followed by C-C bond migration.
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proposed reaction pathways
Key Words
cyclobutanones, pinacol rearrangement, organocatalysis
ID: J48-Y2023
