For the first time, an enolate-mediated organocatalytic vinyl azide-carbonyl [3+ +2] cycloaddition (OrgVACC) of variousk etones/aldehydes with vinyl azides is reported. It is an efficient intermolecular reaction with excellent outcomes with reference to rate, yield, selectivity,o perational simplicity,s ubstrate scope, catalystsimplicity,a nd vast applications.

Organocatalytic azide-ketone [3+2] cycloaddition (OrgAKC) of a variety of 1-aryl-2-(arylthio)ethanones and 1-alkyl-2-(alkylthio)ethanones with different aryl or alkyl azides is reported in dimethyl sulfoxide or solvent-free under ambient conditions to furnish 1,5-disubstituted 4-thio-1,2,3-triazoles in a regiospecific manner, which are further converted into useful 1,5-disubstituted 1,2,3-triazoles by treatment with Raney Ni at 25 °C for 1-3 h. Notable features of the OrgAKC reaction include high rate and selectivity, solvent-free conditions, easily available substrates and catalysts, a wide range of synthetic and medicinal applications, and excellent yields generating a vast library of triazoles.

Herein we report on the 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD) catalyzed enolate‐mediated regiospecific synthesis of 1,4,5‐trisubstituted N‐vinyl‐1,2,3‐triazoles from simple activated carbonyl compounds and N‐vinyl azides through [3+2] cycloaddition; upon further hydrogenation, 1,4,5‐trisubstituted N‐alkyl‐1,2,3‐triazoles are furnished. Both the organo‐click and hydrogenation reactions proceeded in excellent yields with high rates and selectivities at 25 °C within a few hours.

A Ca(OTf) 2 -and self-promoted ynone−amidine atom-economic formal [4 + 2]-cycloaddition of various ynones with amidines is reported for the construction of highly functionalized tricyclic azepines. High reaction rate, ease of operation, and high product selectivity with wide substrate scope are the key advantages of the present annulation protocol.

An enolate mediated aldehyde-azomethine imine [3 + 2] cycloaddition of various aldehydes with N,N-cyclic azomethine imines is reported under DBU or tBuOK-catalysis. High reaction rate, ease of operation, simple catalyst, easily accessible starting materials and a wide substrate scope with numerous applications make this reaction an ideal addition to the click chemistry.[a] J.