Additive-controlled regioselective direct asymmetric aldol reaction of hydroxyacetone and aldehyde

Recent advances in reactions promoted by amino acids and oligopeptides

During the last 20 years, Organocatalysis has become one of the major fields of Catalysis. Herein, we provide a recent overview on reactions where the use of amino acids and peptides as the organocatalysts was employed. All aspects regarding aldol reactions, Michael reactions, epoxidation, Henry reactions and many others that are crucial for the reaction conditions and reaction mechanisms are discussed.

A novel thiourea type organocatalyst possessing a single NH functionality

A novel thiourea organocatalyst was rationally designed by altering a typical H-bonding pattern of thiourea derivatives and utilising the potential of the 3,5-bis(trifluoromethyl)phenyl motif to participate in the H-bond formation. This unique catalyst afforded the products of the α-amination and Michael reaction in excellent yields and with a high level of stereoselectivity. Although additional studies are necessary to establish the full potential of the catalyst and to broaden its application further, the presented results may indicate alternative routes for further exploration of the thiourea class of organocatalysts.

Povarov Reaction of Cycloiminium Formed in Situ via Hydroamination Cycloisomerization of Homopropargylic Amines with Electron-Rich Olefins

A new, one-pot cascade reaction of homopropargylic amines with electron-rich olefins is developed in the presence of Cu(OTf)₂ and affords a series of octahydrofuro[3,2-c]pyrrolo[1,2-a]quinoline derivatives in yields of 38-80%. This reaction proceeds through an intramolecular hydroamination cyclization of homopropargylic amine to generate a highly reactive cycloenamine intermediate in situ that subsequently isomerizes to the cycloiminium cation followed by the Povarov-type reaction with dihydrofuran, dihydropyran, or dihydropyrrole. Notably, the Al₂O₃ additive plays a key role for the effective inhibition of competitive self-dimerization of homoproargylic amines.