Scope and Limitations of Chiral B-[3,5-Bis(trifluoromethyl)phenyl]oxazaborilidine Catalyst for Use in the Mukaiyama Aldol Reaction
Kazuaki Ishihara, Shoichi Kondo, Hisashi Yamamoto*
*Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, IL 60637, Email: yamamotouchicago.edu
K. Ishihara, S. Kondo, H. Yamamoto, J. Org. Chem., 2000, 65, 9125-9128.
DOI: 10.1021/jo001271v (free Supporting Information)
see article for more reactions
A new chiral oxazaborolidine catalyst is much more active than Corey's original catalyst for the Mukaiyama aldol reaction of aldehydes with silyl enol ethers. The observed syn selectivities and re-face attack of silyl enol ethers on carbonyl carbon of aldehydes imply that the extended-transition state model is applicable.
see article for more examples
proposed extended-transition state assembly
M. Wadamoto, N. Ozasa, A. Yanagisawa, H. Yamamoto, J. Org. Chem., 2003, 68, 5593-5601.