A novel C-H functionalization enabled multicomponent reaction involving N-heterocycles, dinucleophile, and dipolarophile has been developed. Direct α- and more challenging β-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.
Metal, oxidant and other additive-free novel methods for direct C–H aryloxylation of aliphatic amines are developed. Divergent reaction for the synthesis of ring-fused oxazine and arylmethylamine is developed.
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.
Regio- and enantioselective direct
arylation of β-alkenyl
pyrroline is reported. A wide range of electron-rich arenes and heteroarenes
reacted under mild conditions with different β-alkenyl pyrrolines
to provide structurally diverse α-aryl-β-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.
The reaction of hydroxy‐aryl aldehydes and ketones with cyclic amines yields either fused oxazines via C—H aryloxylation or arylmethylamines via formal reductive amination depending on stoichiometry and reaction conditions.
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