Pentannulation of N-heterocycles by a tandem gold-catalyzed [3,3]-rearrangement/Nazarov reaction of propargyl ester derivatives: a computational study on the crucial role of the nitrogen atom

The tandem gold(I)-catalyzed rearrangement/Nazarov reaction of enynyl acetates in which the double bond is embedded in a piperidine ring was computationally and experimentally studied. The theoretical calculations predict that the position of the propargylic acetate substituent has a great impact on the reactivity. In contrast to our previous successful cyclization of the 2-substituted substrates, where the nitrogen favors the formation of the cyclized final product, the substitution at position 3 was computed to have a deleterious effect on the electronic properties of the molecules, increasing the activation barriers of the Nazarov reaction. The sluggish reactivity of 3-substituted piperidines predicted by the calculations was further confirmed by the results obtained with some designed substrates.

Zeolites Catalyze the Nazarov Reaction and the tert-Butylation of Alcohols by Stabilization of Carboxonium Intermediates

Zeolites are the most used catalysts worldwide in petrochemistry processes, with particular ability to stabilize carbocations. However, the use of zeolites in organic synthesis is still scarce. We show here that representative carboxonium-mediated organic reactions, such as the Nazarov cyclization and the tert-butylation of alcohols with tert-butyl acetate, typically performed with very strong acid catalysts in solution such as triflic acid, can be catalyzed by simple zeolites with high yield and selectivity. The aluminosilicate framework stabilizes the intermediate carboxonium species and overrides the need for superacid protons in solution.

An allenylidene Au(i) catalyst derived from triazole units and its initial application

First example of allenylidene Au(i) catalyst, based upon alkynyl triazole unit, was developed and utilized in Au(i) mediated Nazarov reaction.

A Novel Aza-Nazarov Cyclization of Quinazolinonyl Enones: A Facile Access to CRing Substituted Vasicinones and Luotonins

Our pre-print titled " A Novel Aza-Nazarov Cyclization of Quinazolinonyl Enones: A Facile Access to C-Ring Substituted Vasicinones and Luotonins" describes:· design and development of a novel variant of aza-Nazarov reaction of quinazolinonyl enones as a methodology to access pyrroloquinazolinones (14 examples)· identification of reaction conditions to achieve two types of pyrroloquinazolinones i.e., linear vs angular, through the intrinsic divergence built in to the enones· detailed computational investigation of the mechanism of this novel cyclization· application in diastereoselctive synthesis of C-ring substituted vasicinones (14 analogues)· application in synthesis of C-ring substituted luotonins (14 analogues)<br>

A Novel Aza-Nazarov Cyclization of Quinazolinonyl Enones: A Facile Access to CRing Substituted Vasicinones and Luotonins

Our pre-print titled " A Novel Aza-Nazarov Cyclization of Quinazolinonyl Enones: A Facile Access to C-Ring Substituted Vasicinones and Luotonins" describes:· design and development of a novel variant of aza-Nazarov reaction of quinazolinonyl enones as a methodology to access pyrroloquinazolinones (14 examples)· identification of reaction conditions to achieve two types of pyrroloquinazolinones i.e., linear vs angular, through the intrinsic divergence built in to the enones· detailed computational investigation of the mechanism of this novel cyclization· application in diastereoselctive synthesis of C-ring substituted vasicinones (14 analogues)· application in synthesis of C-ring substituted luotonins (14 analogues)<br>