Chiral β-Hydroxy Ethers from Spiroborate Ester Mediated Reductions

Significance

β-Hydroxy ethers serve as valuable precursors for many important pharmaceutical compounds. Several enantioselective routes have been developed including ring opening of epoxides catalyzed by salen complexes as well as ring opening of chiral aryl oxiranes. In the present study the authors apply their spiroborate ester 1 to the enantioselective reduction of various ketone ethers to provide the corresponding β-hydroxy ethers in excellent yields and enantiomeric ratios.