Annulation

About: Annulation is a research topic. Over the lifetime, 10152 publications have been published within this topic receiving 189701 citations.

Redox-neutral indole annulation cascades.

Abstract: Aminobenzaldehydes react with indoles in an unprecedented cascade reaction. This acid-catalyzed redox-neutral annulation proceeds via a condensation/1,5-hydride shift/ring-closure sequence. Polycyclic azepinoindoles and related compounds are obtained in a single step with good to excellent yields.

Rhodium-catalyzed regioselective carboacylation of olefins: a C-C bond activation approach for accessing fused-ring systems.

Abstract: Efficiency in the synthesis of a complex molecular target is greatly dictated by the strategy used for building the key skeletal structure. In particular, fused rings are extremely common structural motifs in natural products and drug molecules, and thus access to these motifs through selective and atom-economic methods is of significant importance. Despite the existence of various elegant stepwise cycloaddition methods for building fused-ring systems, we were particularly intrigued by a catalytic “cut-and-sew” reaction, which involves the oxidative addition of a transition metal to a C C bond (Scheme 1). In this type of reaction, a key intermediate, for example, metallocycle B, is formed when

Direct access to benzo[b]furans through palladium-catalyzed oxidative annulation of phenols and unactivated internal alkynes.

Abstract: 2,3-Disubstituted benzo[b]furans are prepared in one step from commercially available phenols and readily accessible unactivated internal alkynes (see scheme). This Pd-catalyzed oxidative annulation has a broad substrate scope and allows access to a wide range of benzo[b]furans.