Phosphine-catalyzed [4+3] annulation reaction of indole deriva-tives
with MBH carbonates: A facile access to indole-1,2-fused
1,4-diazepinones and azepines
Abstract
A phosphine-catalyzed [4+3] annulation between dinucleophilic indole
derivatives and Morita−Baylis−Hillman (MBH) carbonates was discovered by
using the N1 and N4′ or C4′ nucleophilicities of indole precursors,
which provides an efficient and facile access to in-dole-1,2-fused
1,4-diazepinones and azepines in good to high yields in one step, in
which indoles act as four atom synthons. Various transformations of
products illustrate promising applications of the given protocols.