Noninnocent Deep Eutectic Solvents Enable Selective, Sustainable Nickel‐Catalyzed Cross‐Electrophile Couplings to Diarylmethanes
Abstract
We report the first sustainable nickel‐catalyzed cross‐electrophile coupling (XEC) between aryl iodides and benzyl chlorides conducted in a deep eutectic solvent (DES), choline chloride/urea (1:2 mol mol –1 ), replacing the hazardous amide solvents traditionally used in this transformation. The reaction proceeds efficiently under mild (50 °C), aerobic, and heterogeneous conditions, using zinc as the terminal reductant, (dtbbpy)NiBr 2 (2 mol%) as catalyst, and MePh 3 PBr (10 mol%) as additive, delivering a broad range of diarylmethanes in up to 95% yield with wide functional‐group tolerance and gram‐scale applicability within 3 h. Mechanistic and electrochemical studies support a radical/polar crossover pathway in which benzyl radicals, generated off‐cycle from benzyl chlorides, are selectively funneled into productive cross‐coupling through a predominantly Ni(I)/Ni(II)/Ni(III) catalytic manifold rather than diverted into homodimerization. The phosphonium salt appears to modulate nickel speciation, stabilize reduced Ni intermediates, and promote interfacial electron transfer between insoluble substrates and the fraction of nickel catalyst dissolved in the DES. The halide‐rich DES environment likely enhances the reducing power of Zn through Zn 2+ chloride complexation and improved zinc surface activation. Overall, this study establishes DESs as noninnocent media for XEC, providing a sustainable platform beyond conventional volatile organic compound (VOC)‐based solvent systems.
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BibTeX
@article{paparella2026noninnocent,
title = {{Noninnocent Deep Eutectic Solvents Enable Selective, Sustainable Nickel‐Catalyzed Cross‐Electrophile Couplings to Diarylmethanes}},
author = {Andrea Nicola Paparella and Maristella Simone and Alessia Battezzato and Laura Chevet and Laetitia Chausset-Boissarie and Muriel Durandetti and Filippo Maria Perna and Vito Capriati},
journal = {ChemSusChem},
year = {2026},
month = aug,
doi = {10.1002/cssc.70970},
url = {https://normandie-univ.hal.science/hal-05733137v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Noninnocent Deep Eutectic Solvents Enable Selective, Sustainable Nickel‐Catalyzed Cross‐Electrophile Couplings to Diarylmethanes
AU - Andrea Nicola Paparella
AU - Maristella Simone
AU - Alessia Battezzato
AU - Laura Chevet
AU - Laetitia Chausset-Boissarie
AU - Muriel Durandetti
AU - Filippo Maria Perna
AU - Vito Capriati
PY - 2026
DA - 2026/08/20
JO - ChemSusChem
DO - 10.1002/cssc.70970
UR - https://normandie-univ.hal.science/hal-05733137v1
AB - We report the first sustainable nickel‐catalyzed cross‐electrophile coupling (XEC) between aryl iodides and benzyl chlorides conducted in a deep eutectic solvent (DES), choline chloride/urea (1:2 mol mol –1 ), replacing the hazardous amide solvents traditionally used in this transformation. The reaction proceeds efficiently under mild (50 °C), aerobic, and heterogeneous conditions, using zinc as the terminal reductant, (dtbbpy)NiBr 2 (2 mol%) as catalyst, and MePh 3 PBr (10 mol%) as additive, delivering a broad range of diarylmethanes in up to 95% yield with wide functional‐group tolerance and gram‐scale applicability within 3 h. Mechanistic and electrochemical studies support a radical/polar crossover pathway in which benzyl radicals, generated off‐cycle from benzyl chlorides, are selectively funneled into productive cross‐coupling through a predominantly Ni(I)/Ni(II)/Ni(III) catalytic manifold rather than diverted into homodimerization. The phosphonium salt appears to modulate nickel speciation, stabilize reduced Ni intermediates, and promote interfacial electron transfer between insoluble substrates and the fraction of nickel catalyst dissolved in the DES. The halide‐rich DES environment likely enhances the reducing power of Zn through Zn 2+ chloride complexation and improved zinc surface activation. Overall, this study establishes DESs as noninnocent media for XEC, providing a sustainable platform beyond conventional volatile organic compound (VOC)‐based solvent systems.
SN - 1864-5631
SN - 1864-564X
ER -