Efficient 1,4-Addition of Enones and Boronic Acids Catalyzed by a Ni–Zn Hydroxyl Double Salt-Intercalated Anionic Rhodium(III) Complex

Intercalation of an in situ prepared [Rh­(OH)₆]^3– complex into an anion exchangeable Ni–Zn layered hydroxy double salt (Rh/NiZn) was demonstrated. The resulting Rh/NiZn effectively catalyzed the 1,4-addition of diverse enones and phenylboronic acids to their corresponding β-substituted carbonyl compounds. In the case of 2-cyclohexen-1-one and phenylboronic acid, a turnover frequency (TOF) of 920 h^–1 based on Rh was achieved. The [Rh­(OH)₆]^3– complex maintained its original monomeric trivalent state within the NiZn interlayer following catalysis, attributable to a strong electrostatic interaction between the NiZn host and anionic Rh­(III) complex.