The synthesis of N-alkyl-1H-1,2,4-triazoles from N,N-dialkylhydrazones and nitriles via formal [3+2] cycloaddition including the C-chlorination/nucleophilic addition/cyclisation/dealkylation sequence was developed. This sequential reaction utilising the in situ generation of hydrazonoyl chloride based on the ambiphilic reactivity of hydrazones afforded a variety of multi-substituted N-alkyl-triazoles
Enantio‐ and Diastereoselective Nucleophilic Addition of
<i>N</i>
‐
<i>tert</i>
‐Butylhydrazones to Isoquinolinium Ions through Anion‐Binding Catalysis
作者:Esteban Matador、Javier Iglesias‐Sigüenza、David Monge、Pedro Merino、Rosario Fernández、José M. Lassaletta
DOI:10.1002/anie.202012861
日期:2021.3
A highly enantio‐ and diastereoselective thiourea‐catalyzed dearomatization of isoquinolines employing N‐tert‐butylhydrazones as neutral α‐azo carbanions and masked acyl anion equivalents has been developed. Experimental and computational data supports the generation of highly ordered complexes wherein the chloride behaves as a template for the catalyst, the hydrazone reagent, and the isoquinolinium
Sulfonylisocyanates attack the arylaldehyde N,N-dialkylhydrazones 1-3 at the nitrogen or carbon of the azomethine function leading to the formation of the hexahydro-1, 3,5-triazine-2,4-diones 4-6 or arylglyoxylic acid sulfonamide-N, N-dialkylhydrazones 7-9 (scheame 1). Under equal experimental conditions the position of the electrophilic attack depends on the contribution of the dipolar structures