Acetic Acid → (R)-2-Benzhydryloxirane

Participants

Reaction Steps

A mixture of (R,R)-(−)-N,N′-Bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane diaminocobalt (II) (0.22 g, 0.37 mmol, 0.8%), toluene (5 ml), and acetic acid (0.044 g, 0.74 mmol) was stirred for 1 h at room temperature. The solvent was removed in vacuo and the residue was dried. 2-Benzhydryl-oxirane (9.6 g, 45.7 mmol) was added in one portion and stirred, the mixture was then cooled by means of an ice-bath. H2O (0.58 g, 32 mmol) was slowly added over a 30-min period. After water addition, the ice bath was removed and the reaction mixture was stirred at room temperature for 72 h. Compounds were separated via flash chromatography on silica gel column to give (2R)-2-benzhydryl-oxirane (23a) 4.5 g ([α]D=(±)9.58, c=1, MeOH) and (2S)-3,3-diphenyl-propane-1,2-diol 24 3.53 g ([α]D=(±)48, c=1, MeOH, ee=97%). The proton and carbon NMR data of (2R)-2-benzhydryl-oxirane was identical to the racemate 2-benzhydryl-oxirane.

Provenance & Evidence