Synthesis of anhydro-bridged disaccharide subunits of anthracycline antibiotics

Abstract

Following Ferrier glycosylations the hex-2-enopyranosyl disaccharides (5) and (11) are obtained, then converted by allylic oxidation to the Michael-acceptor systems (10) and (13), which are subsequently transformed into the either-bridged disaccharides (14) and (16) by base catalysed intramolecular vinylogue addition; this approach provides the first straightforward access to novel ether-bridged and glycosidically linked saccharide units of anthracycline class II antibiotics such as cinerubin B.