Palladium‐Catalyzed Heck/Insertion/Decarboxylation Domino Sequence: Synthesis of Dihydrocyclohepta[de]naphthalenes

Abstract

A Pd-catalyzed cascade cyclization for the construction of fused dihydrocyclohepta [de] naphthalene skeletons was developed. The skeleton was assembled from 3-iodo-4H-chromen-4-one, norbornene and 8-bromo-1-naphthoic acid. Unlike the classic Catellani reaction, which involves the removal of norbornene, in the present system, norbornene acts as a building block for the construction of rigid nonplanar molecular architectures rather than as an ortho-directing transient mediator. This synthesis involves the formation of three CÀ C bonds via a one-pot process, and it is compatible of a series of substituents.

Palladium/Norbornene Cooperative-Catalyzed Cascade Decarboxylative Cyclization of 4-Iodoisoquinolin-1(2H)-ones with o-Bromobenzoic Acids: Access to Diverse Fused Phenanthridinones and Hepta[1,2-c]isoquinolinones

“…Thus, on the basis of the previously related literature, ,, a plausible mechanism is proposed in Scheme . First, the reaction was initiated by the oxidative addition of Pd(0) to 4-iodoisoquinolin-1(2 H )-ones 1 , followed by migratory insertion and carbopalladation of norbornene to form five-membered aryl-norbornyl-palladacycles (ANP) B .…”

“…Soon after, Liang and Yang reported a Pd/NBE-catalyzed C–H activation and subsequent double decarboxylative coupling reaction of aryl iodides and o -bromobenzoic acids for the synthesis of unsymmetrical triphenylenes (Scheme c) . In 2021, Wu’s group discovered that the five-membered ANP inserted an 8-bromo-1-naphthoic acid to give seven-membered carbocyclic skeletons, which could translate into dihydrocyclohepta­[ de ]­naphthalenes via Pd-catalyzed cascade [3+2+2]­cyclization of 3-iodo-4 H -chromen-4-ones, 8-bromo-1-naphthoic acid, and norbornene (Scheme d) . Norbornene acts as an ortho-directing transient mediator and involves the removal of norbornene by the capture of nucleophiles under the classic Catellani conditions.…”