Mechanistic Study of Pd/NHC‐Catalyzed Sonogashira Reaction: Discovery of NHC‐Ethynyl Coupling Process

Mechanistic Study of Pd/NHC‐Catalyzed Sonogashira Reaction: Discovery of NHC‐Ethynyl Coupling Process Full article

Journal

Chemistry: A European Journal
ISSN: 0947-6539 , E-ISSN: 1521-3765

Output data

Year: 2020, Volume: 26, Number: 67, Pages: 15672-15681 Pages count : 10 DOI: 10.1002/chem.202003533

Authors

Eremin Dmitry B. ^1,2 , Boiko Daniil A. ² , Kostyukovich Alexander Yu. ² , Burykina Julia V. ² , Denisova Ekaterina A. ² , Anania Mariarosa ³ , Martens Jonathan ⁴ , Berden Giel ⁴ , Oomens Jos ⁴ , Roithová Jana ³ , Ananikov Valentine P. ²

Affiliations

1	The Bridge@USC, University of Southern California, 1002 Childs Way, Los Angeles, CA, 90089-3502 USA
2	Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Pr. 47, Moscow, 119991 Russia
3	Department for Spectroscopy and Catalysis, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, Netherlands
4	FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, Netherlands

The product of a revealed transformation—NHC-ethynyl coupling—was observed as a catalyst transformation pathway in the Sonogashira cross-coupling, catalyzed by Pd/NHC complexes. The 2-ethynylated azolium salt was isolated in individual form and fully characterized, including X-ray analysis. A number of possible intermediates of this transformation with common formulae (NHC)nPd(C2Ph) (n=1,2) were observed and subjected to collision-induced dissociation (CID) and infrared multiphoton dissociation (IRMPD) experiments to elucidate their structure. Measured bond dissociation energies (BDEs) and IRMPD spectra were in an excellent agreement with quantum calculations for coupling product π-complexes with Pd0. Molecular dynamics simulations confirmed the observed multiple CID fragmentation pathways. An unconventional methodology to study catalyst evolution suggests the reported transformation to be considered in the development of new catalytic systems for alkyne functionalization reactions.

Eremin D.B. , Boiko D.A. , Kostyukovich A.Y. , Burykina J.V. , Denisova E.A. , Anania M. , Martens J. , Berden G. , Oomens J. , Roithová J. , Ananikov V.P.
Mechanistic Study of Pd/NHC‐Catalyzed Sonogashira Reaction: Discovery of NHC‐Ethynyl Coupling Process
Chemistry: A European Journal. 2020. V.26. N67. P.15672-15681. DOI: 10.1002/chem.202003533 WOS Scopus OpenAlex

≡ Web of science:	WOS:000583859900001
≡ Scopus:	2-s2.0-85093929355
≡ OpenAlex:	W3081994842