Open AccessSuzuki–Miyaura cross-coupling of esters by selective O–C(O) cleavage mediated by air- and moisture-stable [Pd(NHC)(μ-Cl)Cl]2precatalysts: catalyst evaluation and mechanism
Author(s) -
Shiyi Yang,
Tongliang Zhou,
Albert Poater,
Luigi Cavallo,
Steven P. Nolan,
Michal Szostak
Publication year - 2021
Publication title -
catalysis science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.635
H-Index - 115
eISSN - 2044-4761
pISSN - 2044-4753
DOI - 10.1039/d1cy00312g
Subject(s) - catalysis , cleavage (geology) , aryl , chemistry , moisture , coupling (piping) , combinatorial chemistry , medicinal chemistry , polymer chemistry , organic chemistry , materials science , alkyl , fracture (geology) , metallurgy , composite material
The cross-coupling of aryl esters has emerged as a powerful platform for the functionalization of otherwise inert acyl C-O bonds in chemical synthesis and catalysis. Herein, we report a combined experimental and computational study on the acyl Suzuki-Miyaura cross-coupling of aryl esters mediated by well-defined, air- and moisture-stable Pd(II)-NHC precatalysts [Pd(NHC)(μ-Cl)Cl] 2 . We present a comprehensive evaluation of [Pd(NHC)(μ-Cl)Cl] 2 precatalysts and compare them with the present state-of-the-art [(Pd(NHC)allyl] precatalysts bearing allyl-type throw-away ligands. Most importantly, the study reveals [Pd(NHC)(μ-Cl)Cl] 2 as the most reactive precatalysts discovered to date in this reactivity manifold. The unique synthetic utility of this unconventional O-C(O) cross-coupling is highlighted in the late-stage functionalization of pharmaceuticals and sequential chemoselective cross-coupling, providing access to valuable ketone products by a catalytic mechanism involving Pd insertion into the aryl ester bond. Furthermore, we present a comprehensive study of the catalytic cycle by DFT methods. Considering the clear advantages of [Pd(NHC)(μ-Cl)Cl] 2 precatalysts on several levels, including facile one-pot synthesis, superior atom-economic profile to all other Pd(II)-NHC catalysts, and versatile reactivity, these should be considered as the 'first-choice' catalysts for all routine applications in ester O-C(O) bond activation.