RESUMEN
An unprecedented method for the regioselective synthesis of 1,3-diaryl 4-alkyl pyrazoles has been reported. A wide variety of 1,3-diaryl 4-alkyl pyrazoles were synthesized as a single regioisomer via a ring-opening cyclization reaction of unsaturated pyrrolinium ions in the presence of arylhydrazines. This method avoids using additional alkylation steps and hazardous oxidants that generally are essential for the synthesis of 4-alkyl N-arylpyrazoles.
RESUMEN
Regio- and enantioselective direct arylation of ß-alkenyl pyrroline is reported. A wide range of electron-rich arenes and heteroarenes reacted under mild conditions with different ß-alkenyl pyrrolines to provide structurally diverse α-aryl-ß-alkenyl pyrrolidines with very good yields and excellent regioselectivity. Enantioselective reaction in the presence of Lewis acids and chiral phosphoric acids provided the desired arylated product with 73% enantiomeric excess.
RESUMEN
A novel C-H functionalization enabled multicomponent reaction involving N-heterocycles, dinucleophile, and dipolarophile has been developed. Direct α- and more challenging ß-C(sp3)-H functionalization of aliphatic N-heterocycles was achieved without the use of metallic reagents and oxidants under either conventional or microwave aided heating conditions. In a single operation, up to five carbon-carbon and carbon-heteroatom bonds are formed in a highly diastereoselective manner, providing the expeditious access to the complex heteropolycycles.
