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.

An organocatalytic azide−ketone [3 + 2] cycloaddition (OrgAKC) of a variety of 1-aryl-3-(arylthio)propan-2ones and 1-alkyl-3-(arylthio)propan-2-ones with different aryl/ vinyl/alkyl azides is reported under ambient conditions to furnish the medicinally important 1,4-disubstituted-5-arylthiomethyl-1,2,3triazoles and 1,5-disubstituted-4-arylthio-1,2,3-triazoles, respectively, in a regioselective manner with high yields/rates. With controlled and online NMR experiments, we proved that the reaction path is following the organocatalytic enolization through selective deprotonation followed by a [1,3]-H shift. Surprisingly, the [3 + 2] cycloaddition of aryl/vinyl/alkyl azides with the in situ-generated equilibrated thermodynamic ↔ kinetic enolates furnished the highly regioselective functionally rich 1,2,3-triazoles by discriminating their reactivities. This is the first report on the investigation of a selective OrgAKC with the regiomers of enolates generated in situ from the unsymmetrical carbonyl compounds. The reaction sustainability is explained with a few controlled experiments, mechanistic studies, and applications.

Medicinally important 2,3‐diazaspiro[4.5]deca‐3,6‐dien‐1‐ones having vicinal quaternary centers were constructed in very good yields with high enantio‐ and diastereoselectivities through an organocatalytic formal [3+3]‐cycloaddition or domino Michael/aldol reactions, which is driven by the double sequence of in situ isoaromatization and dearomatization steps from the α‐arylidene pyrazolinones and (E)‐alkyl 2‐oxo‐4‐arylbut‐3‐enoates.