European Journal of Organic Chemistry

The preparation of potassium (1-organo-1H-1,2,3-triazol-4-yl)trifluoroborates from potassium ethynyltrifluoroborate and alkyl or aryl halides by employing a regioselective one-pot Cu-catalyzed azide–alkyne cycloaddition (CuAAC) is elaborated. This strategy allows unrestricted access to an infinite variety of 1,4-disubstituted 1,2,3-triazoles.

A two-step protocol for the synthesis of 4,6,7,8,8a,9-hexahydropyrrolo[1,2-a][1,2,3]triazolo[1,5-d]pyrazines was developed. The first step is an AuBr₃-catalyzed three-component coupling of aldehydes, alkynes, and an amine to give propargylamines under solvent-free conditions at 80 °C. The second step is the ring-closure to give the final products under mild reaction conditions.

A highly regioselective synthesis of 5-substituted 3-aminoisoxazoles has been achieved by a one-pot three-component coupling of β-oxo dithioesters, amines and hydroxylamine in ethanol at reflux via an in situ generated β-oxo thioamide intermediate. The mechanism of the reaction has been established experimentally and shown to be in agreement with the HSAB theory.

Benzyloxycarbonyl-protected hybrid hydrazino dipeptides and benzyloxycarbonyl-protected hydrazino aminoacyl conjugates with N-, S-, O-, and C-nucleophiles were prepared by using benzotriazole methodology.

The enantioconvergent conversion of racemic allyl indolenin-3-carboxylates into enantiomerically enriched C3-quaternary indolenines is reported. A Pd-catalyzed decarboxylative allylic alkylation reaction is employed for both stereoablation and enantioselective formation of the quaternary carbon center.