Simple and facile electrocatalytic approach to medicinally relevant spirocyclopropylpyrazolones directly from pyrazoline-5-ones and activated olefins

Metal-free tandem reaction synthesis of spiro-cyclopropyl fused pyrazolin-5-one derivatives

A highly efficient cascade annulation approach was developed for the synthesis of novel spiro-cyclopropyl fused pyrazolin-5-ones from pyrazole-3-ketone substrates and two-component sulfur ylides in an acidic environment.

Electrochemically Induced Michael Addition Reaction: An Overview

Due to its high potential for the formation of carbon-carbon bonds, Michael addition reaction is one of the closest reactions to the heart of synthetic organic chemists. Electrochemistry presents a very stimulating and divergent resource for selective oxidation and reduction in organic chemistry, generating activated species, for example radical anions or radical cations. In this review, we try to underscore usefulness of electrogenerated Michael addition reaction with the hope of encouraging synthetic organic chemists to contemplate it, as an efficient and green strategy when it is required in their designed multi-step reaction pathways.

High diastereoselective amine-catalyzed Knoevenagel-Michael-cyclization-ring-opening cascade between aldehydes, 3-arylisoxazol-5(4H)-ones and 3-aminocyclohex-2-en-1-ones

A highly diastereoselective three-component cascade reaction among aromatic aldehydes, 3-arylisoxazol-5(4H)-ones and 3-aminocyclohex-2-en-1-ones takes place under the catalysis of triethylamine, providing (3SR,4SR)-4-aryl-3-[(E)-(hydroxyimino)(aryl)methyl]-4,6,7,8-tetrahydroquinoline-2,5(1H,3H)-diones in 45-85% yields. The transformation presumably proceeds through a sequential cascade of Knoevenagel/Michael-addition/cyclization/ring-opening reactions. This process was carried out in green media (EtOH/water, 1:1-1:3) at reflux. Products are crystallized directly from the reaction mixture and their isolation includes only filtration. The structure of (3SR,4SR)-3-[(E)-(hydroxyimino)(phenyl)methyl]-7,7-dimethyl-4-phenyl-4,6,7,8-tetrahydroquinoline-2,5(1H,3H)-dione was confirmed by X-ray diffraction analysis.

The first electrocatalytic stereoselective multicomponent synthesis of cyclopropanecarboxylic acid derivatives

Multicomponent electrolysis of aldehydes and two different C–H acids in the presence of NaBr–NaOAc in a simple beaker results in stereoselective formation of trialkyl (2R*,3R*)-3-aryl-2-cyanocyclopropane-1,1,2-tricarboxylates in 52–87% yields.