Catalytic asymmetric synthesis of hydroxy enol ethers: approach to a two-carbon homologation of aldehydes.
[reaction: see text] 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.
Jeon
Sang-Jin
SJ
Department of Chemistry, P. Roy and Diana T. Vagelos Laboratories, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Chen
Young K
YK
Walsh
Patrick J
PJ