Diversity-oriented synthesis of 1,3-benzodiazepines

Synthesis of 1,3-Benzodiazepines through [5 + 2] Annulation of N-Aryl Amidines with Propargylic Esters

In this paper, an efficient synthesis of functionalized 1,3-benzodiazepines through an unprecedented [5 + 2] annulation of N-aryl amidines with propargylic esters is presented. The reactions proceed through Rh(III)-catalyzed C(sp²)-H alkenylation followed by annulation and deacetoxylation along with cascade C-H/N-H/C-O bond cleavage and C-C/C-N bond formation. Furthermore, the cytotoxicity of selected products against several human cancer cell lines was tested, which demonstrated their good potential for pharmaceutical applications.

Palladium-Catalyzed Benzodiazepines Synthesis

This review is focused on palladium-catalyzed reactions as efficient strategies aimed at the synthesis of different classes of benzodiazepines. Several reaction typologies are reported including hydroamination, amination, C–H arylation, N-arylation, and the Buchwald–Hartwig reaction, depending on the different substrates identified as halogenated starting materials (activated substrates) or unactivated unsaturated systems, which then exploit Pd(0)- or Pd(II)-catalytic species. In particular, the use of the domino reactions, as intra- or intermolecular processes, are reported as an efficient and eco-compatible tool to obtain differently functionalized benzodiazepines. Different domino reaction typologies are the carboamination, aminoarylation, aminoacethoxylation, aminohalogenation, and aminoazidation.

Synthesis of pyrrolidinedione-fused hexahydropyrrolo[2,1-a]isoquinolines via three-component [3 + 2] cycloaddition followed by one-pot N-allylation and intramolecular Heck reactions

Two kinds of [3 + 2] cycloaddition intermediates generated from the three-component reactions of 2-bromobenzaldehydes and maleimides with amino esters or amino acids were used for a one-pot N-allylation and intramolecular Heck reactions to form pyrrolidinedione-fused hexahydropyrrolo[2,1-a]isoquinolines. The multicomponent reaction was combined with one-pot reactions to make a synthetic method with good pot, atom and step economy. MeCN was used as a preferable green solvent for the reactions.

Highly Substituted Medium-Sized Ring-Fused Azocinoquinoline Scaffolds by Post-Ugi-4CR Reductive Carbopalladation Cyclization

A concise synthesis of quinoline-fused eight-membered rings from simple starting materials is described. Reductive cyclo-carbopalladation of suitable Ugi-4CR substrates as a key step leads to the regio- and diastereoselective formation of 1,2-dihydroazocino[4,3-b]quinolin-3-ones under mild reaction conditions with good yields in short reaction time.

Reactions of secondary propargylamines with heteroallenes for the synthesis of diverse heterocycles

This focused review aims to summarize recent developments in the processes involving additions of secondary propargylamines to various heteroallenes and subsequent transition metal-catalyzed or electrophile-mediated cyclizations.