Mono-etherification of racemic propane-1,2-diol by a tin(II) bromide catalyzed reaction with diazofluorene and a study of the Pseudomonas cepacia lipase catalyzed acetylation of the mono-ethers

The tin(II) bromide catalyzed reaction of diazofluorene with racemic propane-1,2-diol in 1,2-dimethoxymethane gave the 1- and 2-monoethers in similar amounts. After tritylation of the 2-ether, 2-(9H-fluoren-9-yloxy)-1-triphenylmethyloxypropane and 1-(9H-fluoren-9-yloxy)propan-2-ol were obtained in pure form. The enantiomeric 1-fluorenyl ethers were resolved by kinetic resolution by transacetylation with the help of Pseudomonas cepacia lipase and both enantiomers of the propane-1,2-diol were obtained after deprotection. The racemic 2-(9H-fluoren-9-yloxy)propan-1-ol was obtained after de-triphenylmethylation. However, transacetylation onto this alcohol under identical conditions to those used for the 1-fluorenyl ether showed no enantioselectivity. (C) 2012 Elsevier Ltd. All rights reserved.