Formal total syntheses of Myxothiazols by three different approaches starting from benzyloxyacetaldehyde

An efficient entry into the key intermediate for the total synthesis of myx othiazol A(1) and related structures is described. We investigated three di fferent approaches for building up the carbon framework starting from benzy loxyacetaldehyde and subjecting this to an aldol reaction, a titanium tetra chloride-mediated aldol reaction of a protected beta-ketoester and a Barbie r-type reaction using zinc or indium, respectively. The latter proved to be the longer (seven steps), but more efficient route, with 15% overall yield . (C) 2000 Elsevier Science Ltd. All rights reserved.