A FACILE CONSTRUCTION OF 4-HYDROXYMETHYLBENZISOTHIAZOLONE-1,1-DIOXIDE

4-Hydroxymethylbenzisothiazolone-1,1-dioxide could be facilely synthes ised via a highly regioselective Diels-Alder cycloaddition between fur furyl alcohol and 2-(tert-butyl)-isothiazolone-1,1-dioxide, followed b y aromatization of the adduct under basic conditions. A secondary effe ct from intramolecular hydrogen bonding is found also to influence the regioselectivity of the cycloaddition. Unequivocal proof of the regio chemistry of the Diels-Alder reaction is provided by X-ray crystallogr aphy and ab initio calculations showed electronic and steric effects o n transition structure asynchronicity. (C) 1998 Elsevier Science Ltd. Ail rights reserved.