Enantiopure dihalocyclopropyl alcohols and esters by lipase catalyzed kinetic resolution

Four halogenated cyclopropane derivatives with a side chain containing a primary (1 and 2) or secondary (3 and 4) alcohol moiety were subject to kinetic resolution catalyzed by lipases. Two of them containing secondary alcohol groups gave excellent results with Candida antarctica lipase B with E-values around 1000. Two enantiopure alcohols and two enantiopure butanoates are described: (1S,1′S)-1-(2′,2′-dichloro-3′,3′-dimethylcyclopropyl) ethanol (3), the corresponding (1R,1′R)-butanoate (3b) and (1S,1′S)-1-(1′-methyl-2′,2′-dibromocyclopropyl) ethanol (4) and the corresponding (1R,1′R)-butanoate (4b).