Regioselective bromohydroxylation of alkenes catalyzed by chloroperoxidase: Advantages of the immobilization of enzyme on talc

The bromohydroxylation of alkenes catalyzed by chloroperoxidase (CPO) from the mould Caldariomyces fumago adsorbed on different types of talc or in reverse micelles was compared to that of the same reaction catalyzed by the free enzyme in buffer. High reactivity was observed in all media, but the reaction was optimized with an enzyme-talc combination that produced the halohydrin with no oxidative by-products in a Markovnikov-type regioselective addition. The reaction was facilitated by the use of this solid and a recyclable biocatalyst, which gave rise to the halohydrin in a quantitative yield. The protective influence of the talc (hydrophilic or hydrophobic) with respect to hydrogen peroxide enabled use of large amounts of oxidizing agent and substrate, opening perspectives for CPO in the synthesis of fine chemicals. (C) 1998 Elsevier Science B.V.