Resolution of a racemic 1,2-diol using triphenylmethyl protection of the primary hydroxyl group and Mucor miehei lipase (Lipozyme) for the kinetic resolution

The triphenylmethyl group gives very simple access to the 1-protection of 1,2-diol as exemplified by racemic propane-1,2-diol. This group has, however, been shown to be incompatible with lipases commonly used for the resolution of alcohols. This turned out to be the case for Pseudomonas cepacia lipase, which we have used in our earlier work. Lipozyme, a Mucor miehei lipase, best known for 1,3-selectivity with glycerol is, however, shown to catalyze transacetylation onto the secondary hydroxyl group next to a triphenylmethoxy group. The transacetylation is completely enantioselective for the (R)-enantiomer giving a very simple method for the resolution of this type of 1,2-diol enantiomer.

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(R)-2-Acetoxy-1-triphenylmethoxypropaneC24H24O3[α]D20=+18.1 (c 1.01 CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (R)

(S)-1-Triphenylmethoxypropan-2-olC22H22O2[α]D20=+4.7 (c 1.02 CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (S)

(S)-Propane-1,2-diolC3H8O2[α]D20=-29.3 (c 1.95 CHCl3)Source of chirality: enzymatic resolutionAbsolute configuration: (S)