Proline and Lewis base co-catalyzed addition of α,β-unsaturated aldehydes to nitrostyrenes

Peptide catalyzed regio- and enantioselective ε-alkylation of γ-branched 2,4-dienals via trienamine activation

The regio- and enantioselective ε-alkylation of γ-branched 2,4-dienals was successfully achieved via trienamine catalysis. N-Terminal prolyl pentapeptide with a turn structure was effective as a catalyst for this transformation.

Regiodivergent Organocatalytic Reactions

Organocatalysts are abundantly used for various transformations, particularly to obtain highly enantio- and diastereomeric pure products by controlling the stereochemistry. These applications of organocatalysts have been the topic of several reviews. Organocatalysts have emerged as one of the very essential areas of research due to their mild reaction conditions, cost-effective nature, non-toxicity, and environmentally benign approach that obviates the need for transition metal catalysts and other toxic reagents. Various types of organocatalysts including amine catalysts, Brønsted acids, and Lewis bases such as N-heterocyclic carbene (NHC) catalysts, cinchona alkaloids, 4-dimethylaminopyridine (DMAP), and hydrogen bond-donating catalysts, have gained renewed interest because of their regioselectivity. In this review, we present recent advances in regiodivergent reactions that are governed by organocatalysts. Additionally, we briefly discuss the reaction pathways of achieving regiodivergent products by changes in conditions such as solvents, additives, or the temperature.

Microwave-assisted organic acid–base-co-catalyzed tandem Meinwald rearrangement and annulation of styrylepoxides

A microwave-assisted acid and base co-catalyzed strategy shows very high efficiency in the tandem reaction for the conversion of styrylepoxides into [1,1′-biaryl]-3-carbaldehydes.

Organocatalytic enantio- and diastereoselective conjugate addition to nitroolefins: when β-ketoamides surpass β-ketoesters

Our findings on the bifunctional squaramide-catalyzed enantioselective conjugate addition of β-ketoamides to nitroolefins are disclosed. It appears that simple acyclic methylene β-ketoamides, unlike the extensively studied β-ketoesters, afford the products in excellent diastereoselectivities, and maintain high yields and enantioselectivities. Moreover, competition and kinetic studies were conducted to rationalize the observed reactivity and selectivity. The high level of diastereocontrol, along with the amenability of the amide group to postfunctionalization, dramatically increase the synthetic usefulness of the transformation.