A novel biotransformation of benzofurans and related compounds catalysed by a chloroperoxidase

The oxidation of 3-alkyl benzofurans, indoles, and a benzothiophene by the chloroperoxidase from Caldariomyces fumago has been investigated. Under con ditions in which the catalase activity of chloroperoxidase was minimised in the presence of chloride and hydrogen peroxide, 3-methylbenzodiiophene was oxidised at sulfur but the indoles (5-9) and benzofurans (1-4) gave 2,3-di ols as initial products. In the case of N-unsubstituted indoles, these taut omerised to give the corresponding lactam. In contrast, the diols (predomin antly trans) formed from the benzofurans were sufficiently stable for isola tion and full characterisation. This novel reaction has the. potential to b e developed into a useful synthetic biotransformation. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.