Acetophenone → 1-Phenylethanol

A solution of (S)-(-)-α,-α-diphenyl-2-pyrrolidinemethanol (DPP) (Aldrich) (1.02 g, 4.03 mmol) in carefully dried THF (4 mL) was added to a solution of sodium aluminum hydride in THF (4.85 mL of 0.252M solution, 1.25 mmol) with stirring under argon at r.t. for 5 min, 45.5 cm3H2 being evolved (calcld. 56 mL for AlH2 complex formation). 1.2 mL of the solution thus obtained was placed by syringe in another flask, and was allowed to stand at r.t. for 1 h. The solution was cooled to +70° C. and acetophenone (0.6 mL of 0.133M solution in THF, 0.083 mmol) was added. Within 24 h (-70° C.) the first probe of reaction mixture was taken and analyzed by GC (30 m capillary column, stationary phase was pentylated and trifluoroacetylated γ-cyclodextrine). GC analysis gave 86% conversion of AP into 1-phenylethanol, e.e. 69% (R). After an additional 24 h, the reaction mixture was warmed to -20° C. and was allowed to stand at this temperature for 4 days. GC analysis of the reaction mixture gave conversion of AP 88% and e.e. value 70% (R). After an additional 3 days, the reaction mixture was hydrolyzed using MeOH-ether (1:10) until evolution of H2 ceased. The mixture was diluted by 4-fold volume of ether and extracted by 10% HCl to remove the aluminum compounds and the ligand. The ether layer was separated and analyzed by GC: conversion of AP 91%., e.e. 67% (R).

1. customwas placed by syringe in another flask
2. temperatureThe solution was cooled to +70° C.
3. customWithin 24 h (-70° C.) the first probe of reaction mixture

ORD record

ord-d00ec3b43b2a4669949db337c8554f85

Source dataset

uspto-grants-2000_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06090950