Heck-type coupling of intramolecularly-generated thiopalladacycles with alkenes: One pot syntheses of 3-alkenylbenzo[b]thiophenes

Palladium-Catalyzed Aminocyclization-Coupling Cascades: Preparation of Dehydrotryptophan Derivatives and Computational Study

Dehydrotryptophan derivatives have been prepared by palladium-catalyzed aminocyclization-Heck-type coupling cascades starting from o-alkynylaniline derivatives and methyl α-aminoacrylate. Aryl, alkyl (primary, secondary, and tertiary), and alkenyl substituents have been introduced at the indole C-2 position. Further variations at the indole benzene ring, as well as the C-2-unsubstituted case, have all been demonstrated. In the case of C-2 aryl substitution, the preparation of the o-alkynylaniline substrate by Sonogashira coupling and the subsequent cyclization–coupling cascade have been performed in a one-pot protocol with a single catalyst. DFT calculations have revealed significant differences in the reaction profiles of these reactions relative to those involving methyl acrylate or methacrylate, and between the reactions of the free anilines and their corresponding carbamates. Those calculations suggest that the nature of the alkene and of the acid HX released in the HX/alkene exchange step that precedes C–C bond formation could be responsible for the experimentally observed differences in reaction efficiencies.

Recent Progress in the Synthesis of Benzo[b]thiophene

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Due to such a wide range of applicability, the synthesis of benzo[b]thiophene derivatives has attracted intensive research. Numerous mild and efficient approaches for the synthesis of benzo[b]thiophenes have been developed over the years. Different catalysts and substrates have been applied for benzo[b]thiophene synthesis. This review will focus on the studies in the construction of benzo[b]thiophene skeleton, which date back from 2012.

Trifluoroacetimidoyl halides: a potent synthetic origin

In the review, recent advances in the synthetic applications of trifluoroacetimidoyl halides have been summarized.

Palladium catalyzed domino reaction of 1,4-disubstituted 1,2,3-triazoles via double C–H functionalization: one-pot synthesis of triazolo[1,5-f]phenanthridines

A palladium catalyzed domino reaction of 1,4-disubstituted triazoles involving homo- and heterocondensation is presented. The approach provides a simple, straight forward and a facile route to access triazolo[1,5-f]phenanthridines in high yields.

An expedient approach to pyrrolo[3,2-c]quinolines via regioselective formation of the pyrrole nucleus over indoles

The regioselective synthesis of pyrrolo[3,2-c]quinolines from protected 2-alkynylanilines by Heck and intramolecular Michael addition has been described.