Bench-Stable Cerium(IV) Benzoate: A Versatile LMCT Catalyst for Selective Dehydroxymethylative Functionalization
Hanwen Liang, Linmei Lai, Kaining Zhang, Wenlong Chen, Mingfeng Li, Yi Yang, Jian Li, Zhiwei Zuo
Abstract
Dehydroxymethylation offers intriguing synthetic opportunities to exploit the ubiquitous C–C bonds in free alcohols as unconventional functional handles; however, its synthetic potential has been constrained by the development of efficient catalysts. In this work, we introduce a robust, bench-stable cerium(IV) benzoate complex, [Ce(TRIPCO 2 ) 5 Na], which functions as an efficient ligand-to-metal charge transfer (LMCT) catalyst, enabling selective cleavage of α-C(sp 3 )–C(sp 3 ) bonds in free alcohols. This cerium(IV) catalyst is straightforward to synthesize on a gram scale, providing simple conditions for dehydroxymethylation reactions while eliminating the need for exogenous halide additives. The catalytic efficiency of this complex has been demonstrated in the dehydroxymethylative amination of free alcohols and the seamless one-pot synthesis of N -alkyl pyrazoles. Furthermore, the cerium-LMCT catalyst demonstrates efficacy within a metallaphotoredox paradigm, where the synergistic interplay between cerium-LMCT and nickel catalysis facilitates dehydroxymethylative alkylation, enabling the efficient utilization of alcohol feedstocks for selective C(sp 3 )–C(sp 3 ) cross-coupling reactions. Mechanistic investigations have elucidated the photoexcitation and redox properties, revealing the selective generation of alkoxy radical intermediates in the presence of benzoate ligand, a critical factor in enabling radical-mediated bond cleavage.