Acetal formation by solvolysis of glucal-derived donor-acceptor cyclopropanes

The conversion of glucal derived donor-acceptor cyclopropanes to acetals by TiCl4 mediated ring opening and alcohol trapping is described. Good selectivity for the alpha anomer and yields near 90% are consistently observed with aliphatic, benzylic and allylic alcohols, phenols and thiophenols. The utility of this method to prepare oligosaccharides through intermediate O,S-acetals is illustrated. (C) 2003 Elsevier Science Ltd. All rights reserved.