Catalytic Asymmetric Synthesis of
Hydroxy Enol Ethers: Approach to a
Two-Carbon Homologation of Aldehydes
Sang-Jin Jeon,Young K. Chen, andPatrick J. Walsh*
Department of Chemistry, P. Roy and Diana T. Vagelos Laboratories,
University of Pennsylvania, Philadelphia, Pennsylvania 19104
pwalsh@sas.upenn.edu
Received February 7, 2005
Abstract:
Hydroboration of ethoxy acetylene, transmetalation to zinc, and addition to aldehydes in the presence of a chiral amino alcohol ligand (MIB)
affords hydroxy enol ethers with high ee. The resultant enantiomerically enriched hydroxy enol ethers were converted to protected hydroxy
aldehydes, a useful synthetic building block for the construction of a variety of polyoxygenated natural products. In addition, diastereoselective
formation of syn- and anti-1,3-diols was studied.
