Efficient Synthesis of the 3-Benzazepine Framework via Intramolecular Heck Reductive Cyclization

Abstract

A microwave-assisted protocol based on reductive Heck reaction was developed for regio- and stereoselective construction of the 3-benzazepine core.

Diversity‐Oriented Synthesis of Intensively Blue Emissive 3‐Hydroxyisoquinolines by Sequential Ugi Four‐Component Reaction/Reductive Heck Cyclization

“…Triphenylphosphine was not effective at all (Table 1, entry 1), whereas formic acid, which has been used either as the free acid or as the sodium salt in the reductive Heck cyclization, [30] gave encouraging results with a noticeable increase of both the yield and the reproducibility.…”

Synthesis of Ring‐Expanded Aza‐Analogues of Bisbenzocyclooctadiene Lignan Lactones

“…Variation of reaction conditions failed to suppress this process. In contrast, when the reaction was performed in the presence of a reducing agent as, for example, sodium formate, compound 3a was regio-and stereoselectively cyclized into the 3-benzazepine compound 11 via a reductive Heck reaction mechanism [8] (Scheme 3). To avoid complications associated with the reaction of the acetylenic moiety, we switched to the cross-coupling reaction of the BOC-protected amine.…”

“…Obviously, this isomerism could be ascribed to the conformational rigidity of the 11-membered ring encumbered by a bulky PBM group. In order to reduce the conformational strain the PMB-protecting group was removed under acidic conditions applying microwave irradiation [8,12]. Indeed, the corresponding deprotected cyclic secondary amides 1a -e were obtained as single conformers.…”

Recent Developments in Microwave‐Assisted, Transition‐Metal‐Catalysed C–C and C–N Bond‐Forming Reactions

“…[50] As a result of the reaction mechanism, the formation of the medium-sized ring occurred with full regio-and stereoselectivity. The 4-hydroxycyclohexa-2,5-dien-1-one ("quinol") fragment represents a new pharmacophore in anticancer drug development.…”