Catalytic Asymmetric Generation of (Z)-Disubstituted Allylic Alcohols
Luca Salvi, Sang-Jin Jeon, Ethan L. Fisher, Patrick J. Carroll and Patrick J. Walsh*
*P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, Email: pwalshsas.upenn.edu
L. Salvi, S.-J. Jeon, E. L. Fisher, P. J. Carroll, P. J. Walsh, J. Am. Chem. Soc., 2007, 129, 16119-16125.
DOI: 10.1021/ja0762285 (free Supporting Information)
Hydroboration of 1-halo-1-alkynes with dicyclohexylborane, reaction with t-BuLi, and transmetalation with dialkylzinc reagents generate (Z)-disubstituted vinylzinc intermediates. A subsequent reaction with aldehydes in the presence (-)-MIB generates (Z)-disubstituted allylic alcohols. Addition of tetraethylethylenediamine inhibits a fast, LiCl-promoted addition leading to racemic products.
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Y. K. Chen. A. E. Lurain, P. J. Walsh, J. Am. Chem. Soc., 2002, 124, 12225-12231.