TMSN3-Bu2Sn(OAc)2: A modified and mild reagent system for Wittenberger tetrazole-synthesis

Palladium(0)-Catalyzed Enantioselective Construction of Multifunctional Piperidine Derivatives from 1,3-Dienes, N-Cyano Imines, and Beyond

An enantioselective (4 + 2) reaction between 1,3-dienes and N-cyano imines has been developed under Pd(0) catalysis, proceeding through a cascade vinylogous addition and intramolecular allylic amination sequence. 2,6-cis-Disubstituted-1,2,3,6-tetrahydropyridines were furnished as single diastereomers in moderate to good yields and enantiocontrol. Moreover, a more challenging three-component (2 + 2 + 2) annulation of 1,3-dienes, N-cyano imines, and activated alkenes was efficiently realized to afford piperidines with high structural complexity, albeit with moderate enantioselectivity.

Direct Catalytic Enantioselective Reaction of α-Isocyanoacetonitriles with Ketimines Using Cinchona Alkaloid Amide-Cu(II) Catalysts

The first enantioselective reaction of α-isocyanoacetonitriles was developed. The reaction of various α-isocyanoacetonitriles with ketimines using cinchona alkaloid amide-Cu(II) catalysts afforded imidazolines with consecutive tetrasubstituted stereogenic carbon centers in good yields and high diastereo- and enantioselectivities. The stereoselectivity of the reaction is explained on the basis of the control experiment and density functional theory (DFT) calculations. The products were subsequently converted into chiral compounds. This process highlights the possible use of α-isocyanoacetonitriles for asymmetric and organic syntheses.

Enantioselective reaction of N-cyano imines: decarboxylative Mannich-type reaction with malonic acid half thioesters

The enantioselective reaction of imines bearing a cyano group as an activating group with malonic acid half thioesters gave chiral cyanamide derivatives with high enantioselectivity. The density functional theory (DFT) calculation clarified the stereochemical outcome and importance of the N-cyano group for imines.

Understanding the regioselectivity of 5-substituted 1H-tetrazoles alkylation

A novel rational to account for the selectivity of 5-substituted 1H-tetrazole alkylation.

Alkylation of 5-Substituted 1H-Tetrazoles via the Diazotization of Aliphatic Amines

A new alkylation reaction of monosubstituted tetrazoles via the diazotization of aliphatic amines is reported. This method enables preferential formation of 2,5-disubstituted tetrazoles. A one-pot 1,3-dipolar cycloaddition/diazotization sequence starting from widely available nitriles is also described. Azide residues are quenched in the second step with the nitrite reagent, thus limiting the intrinsic risk associated with trimethylsilyl azide. The reaction conditions were compatible with several functional groups, including thiocyanates, which afford preferentially disubstituted 2-alkyl-5-(substituted-thio)tetrazoles.