The kinetic resolutions of rac-1-phenylethanol and rac-2-pentanol by transesterification with vinyl esters catalysed by a commercial immobilised Candida antarctica lipase B were successfully carried out in hexane medium This enzyme showed very high enantioselectivity for both substrates The influence of the water content of the medium on the synthetic activity, selectivity and enantioselectivity of the enzyme was analysed, with the optimal amount of water about 100 ppm Our results also showed that the activity per gram enzymatic derivate of CaLB was slightly higher with butyl butyrate as acyl donor