Covalent organic framework supported Pd(II)‐catalyzed conjugate additions of arylboronic acids to α,β‐unsaturated carboxylic acids

Abstract

A palladium(II)‐coordinated covalent organic framework (Pd(II)@COF) was mechanochemically synthesized from [2,2′‐bipyridine]‐5,5′‐diamine (Bpy) and 1,3,5‐triformylphloroglucinol (Tp), which was demonstrated as a catalyst for conjugate addition of arylboronic acids to unreactive α,β‐unsaturated carboxylic acids in aqueous media (water/acetone = 1:1). Modest to good yields were obtained for most substrates, and studies on the catalyst recyclability showed that the heterogeneous catalyst gave >80% yields in the first 4 cycles. This research broadens the application of COFs supported catalysis and gave a new option for Pd(II)‐catalysis.

Metalated covalent organic frameworks: from synthetic strategies to diverse applications

“…46E). 225 The yield was maintained at more than 70% after five catalytic cycles. The same year, Ma et al reported an interesting Pd( ii )-loaded COF catalyst based on an imine-linked dual-pore COF which can catalyse regioselective hydrocarbon activation reaction of benzo[ h ]quinoline in a heterogeneous way (Fig.…”

“…224 However, the mechanochemical synthesis can circumvent this issue, but the obtained Pd( ii )-metalated Pd-TpBpy COF has poor crystallinity. 225 In addition, the room temperature synthesis of COFs is also a feasible approach, 226 but may not meet the high crystallinity requirements of most COFs. The attempt to synthesize Re( i )-chelated 2,2′-bipyridine-COFs, however, was successful.…”

Design, synthesis, and application of covalent organic frameworks as catalysts

“…Therefore, refinement of the solvothermal method has been used to increase the crystallinity of the synthesized compound, and, consequently, a refined COF can be obtained. 82…”

Covalent organic framework supported palladium catalysts

“…A range of β-arylated carboxylic acids could be synthesized using Pre-Pd( ii )@COF as a catalyst, in medium to excellent yields (21 to 94%). 67…”