Advances in siloxane-based coupling reactions: Application of palladium-mediated allyl-aryl coupling to the synthesis of pancratistatin derivatives. The formal total synthesis of (±)-7-deoxypancratistatin

Article abstract of DOI:10.3987/COM-12-S(N)35

Palladium-mediated coupling of an allylic carbonate and an aryl siloxane has been applied to the formal total synthesis of 7-deoxypancratistatin and pancratistatin analogues. The key coupling reaction involved the use of a novel palladium olefin complex resulting in regio- and stereoselective arylation yielding a tetracyclic A-C ring intermediate. The observed regioselectivity of the coupling reaction was consistent with a model in which an unsymmetrical p-allyl palladium complex was formed. Coupling of a variety of substituted phenyl siloxane derivatives was achieved using the new Pd(0) system to provide access to novel pancratistatin derivatives.