Rh‐Catalyzed Direct Carboxylation of Alkenyl C−H Bonds of Alkenylpyrazoles

Abstract

The Rh-catalyzed direct carboxylation of alkenyl C-H bonds was achieved by using pyrazole as a removable directing group. In the presence of 5 mol% RhCl₃ ⋅ 3H₂ O, 6 mol% P(Mes)₃ , and 2 equiv. of AlMe₂ (OMe), the alkenyl C-H bond of various alkenylpyrazoles was directly carboxylated in good yields under CO₂ atmosphere. Furthermore, several useful transformations of the pyrazole moiety of the product were achieved to afford synthetically useful carboxylic acid derivatives in good yields.