"Diphenylprolinol"

to 10% catalytic loads of the spiroborate 5 derived from diphenylprolinol and ethylene glycol.

Spiroborate Ester-Mediated Asymmetric Synthesis of β-Hydroxy Ethers and its Conversion to Highly Enantiopure β-Amino Ethers Borane-mediated reduction of aryl and alkyl ketones with alpha-aryl- and alpha-pyridyloxy groups affords beta-hydroxy ethers in high enantiomeric purity (up to 99% ee) and in good yield, using as catalyst 10 mol % of spiroborate ester 1 derived from (S)-diphenylprolinol