Recent applications of ninhydrin in multicomponent reactions

Ninhydrin (1,2,3-indanetrione hydrate) has a remarkable breadth in different fields, including organic chemistry, biochemistry, analytical chemistry and the forensic sciences. For the past several years, it has been considered an important building block in organic synthesis. Therefore, there is increasing interest in ninhydrin-based multicomponent reactions to rapidly build versatile scaffolds. Most of the works described here are simple reactions with readily available starting materials that result in complex molecular architectures. Some of the synthesized compounds exhibit interesting biological activities and constitute a new hope for anticancer agents. The present review aims to highlight the multicomponent reactions of ninhydrin towards diverse organic molecules during the period from 2014 to 2019.

This article aims to review recent multicomponent reactions of ninhydrin towards diverse organic scaffolds, such as indeno-fused heterocycles, spiro-indeno heterocycles, quinoxalines, propellanes, cage-like compounds, and dispiro heterocycles.

Ethyl 6′-cyano-7′-phenyl-1′,6′,7′,7a'-tetrahydro-3′H-spiro[indeno[1,2-b]quinoxaline-11,5′-pyrrolo[1,2-c]thiazole-6′-carboxylate

In the title compound, C22H22ClN4O2S, the angle between the mean planes of the indene ring and the quinoxaline ring system is 3.93 (11)°. The five-membered indene and thiazole rings both adopt envelope conformations while the pyrrole ring adopts a twisted conformation. The two acceptor O atoms form a chelated three-centred hydrogen bond with a phenyl C atom.

Synthesis of Sulfur-Containing Exo-Bicyclic Dienes and Their Diels-Alder Reactions To Access Thiacycle-Fused Polycyclic Systems

The stereocontrolled synthesis of unprecedented sulfur-containing exo-bicyclic 1,3-dienes is reported through a palladium-catalyzed reductive cyclization of sulfur-linked 2-bromoenynes. The fused bicyclic structure provides a better stability to the thiacyclic diene compared to the simple 3,4-dimethylenetetrahydrothiophene. Their reactivity toward several dienophiles has been investigated, and various original thiacycle-fused polycyclic systems have been obtained with high or total diastereoselectivity. Moreover, they are the first exo-bicyclic dienes used in Diels-Alder reactions. The relative configurations of four cycloadducts have been unambiguously assigned by X-ray crystallographic analysis. Mechanistic details of the cycloadditions have been examined by computational means.

A highly diastereoselective one-pot three-component 1,3-dipolar cycloaddition of cyclopropenes with azomethine ylides generated from 11H-indeno[1,2-b]-quinoxalin-11-ones

A simple and efficient synthesis of compounds with spiro-fused 11H-indeno[1,2-b]quinoxaline and azabicyclo[3.1.0]hexane or cyclopropa[a]pyrrolizine moieties was developed.

Mechanistic insight into the acid-catalyzed isomerization of biomass-derived polysubstituted pyrrolidines: an experimental and DFT study

The mechanism of the acid-catalyzed isomerization of polysubstituted pyrrolidines was unravelled by a combination of experimental, spectroscopic and computational studies.

A theoretical study of the activation of nitromethane under applied electric fields

C–N activation is the key step of nitromethane decomposition.

Mechanistic and stereoselectivity study for the reaction of trifluoropyruvates with arylpropenes catalyzed by a cationic Lewis acid rhodium complex

The mechanism and stereoselectivity of a Lewis acid catalyzed carbonyl–ene reaction of trifluoropyruvates with arylpropenes have been investigated using a DFT method.