Capture of reactive monophosphine-ligated palladium(0) intermediates by mass spectrometry

Qiuling Zheng; Yong Liu; Qinghao Chen; Meihong Hu; Roy Helmy; Edward C Sherer; Christopher J Welch; Hao Chen

doi:10.1021/jacs.5b08905

Capture of reactive monophosphine-ligated palladium(0) intermediates by mass spectrometry

J Am Chem Soc. 2015 Nov 11;137(44):14035-8. doi: 10.1021/jacs.5b08905. Epub 2015 Oct 28.

Authors

Qiuling Zheng¹, Yong Liu², Qinghao Chen², Meihong Hu¹, Roy Helmy², Edward C Sherer², Christopher J Welch², Hao Chen¹

Affiliations

¹ Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University , Athens, Ohio 45701, United States.
² Department of Process and Analytical Chemistry and Department of Structural Chemistry, Merck Research Laboratories, Merck & Co., Inc. , Rahway, New Jersey 07065, United States.

PMID: 26498505
DOI: 10.1021/jacs.5b08905

Abstract

A long-sought-after reactive monophosphine-ligated palladium(0) intermediate, Pd(0)L (L = phosphine ligand), was detected for the first time from the activation of the Buchwald precatalyst with base. The detection was enabled using desorption electrospray ionization mass spectrometry (DESI-MS) in combination with online reaction monitoring. The subsequent oxidative addition of Pd(0)L with aryl halide and C-N coupling with amine via reductive elimination was also probed using DESI-MS.