Stille coupling via C-N bond cleavage.

Dong-Yu Wang,Ze-Kun Yang,Chao Wang,Masanobu Uchiyama,Kentaro Yamaguchi,Masatoshi Kawahata,Shinsuke Komagawa,Kazunori Miyamoto

doi:10.1038/ncomms12937

Abstract

Cross-coupling is a fundamental reaction in the synthesis of functional molecules, and has been widely applied, for example, to phenols, anilines, alcohols, amines and their derivatives. Here we report the Ni-catalysed Stille cross-coupling reaction of quaternary ammonium salts via C–N bond cleavage. Aryl/alkyl-trimethylammonium salts [Ar/R–NMe3]+ react smoothly with arylstannanes in 1:1 molar ratio in the presence of a catalytic amount of commercially available Ni(cod)2 and imidazole ligand together with 3.0 equivalents of CsF, affording the corresponding biaryl with broad functional group compatibility. The reaction pathway, including C–N bond cleavage step, is proposed based on the experimental and computational findings, as well as isolation and single-crystal X-ray diffraction analysis of Ni-containing intermediates. This reaction should be widely applicable for transformation of amines/quaternary ammonium salts into multi-aromatics.

Highlights

Cross-coupling is a fundamental reaction in the synthesis of functional molecules, and has been widely applied, for example, to phenols, anilines, alcohols, amines and their derivatives
We show that the reaction mediated by commercially available Ni-catalyst/imidazole ligand and CsF provides high synthetic efficiency and broad functional group compatibility
Aryltrimethylammonium salts 1 were readily synthesized from various anilines/amines bearing NH2, NHMe or NMe2 groups (Fig. 1)

Summary

Introduction

Cross-coupling is a fundamental reaction in the synthesis of functional molecules, and has been widely applied, for example, to phenols, anilines, alcohols, amines and their derivatives. We report the Ni-catalysed Stille cross-coupling reaction of quaternary ammonium salts via C–N bond cleavage. The reaction pathway, including C–N bond cleavage step, is proposed based on the experimental and computational findings, as well as isolation and single-crystal X-ray diffraction analysis of Ni-containing intermediates. This reaction should be widely applicable for transformation of amines/ quaternary ammonium salts into multi-aromatics. Quaternary organo-ammonium salts can be prepared from various aryl/alkyl amines Their potential usage in cross-coupling was pioneered by Wenkert et al.[26] (Ni-catalyst and Grignard reagent). We show that the reaction mediated by commercially available Ni-catalyst/imidazole ligand and CsF provides high synthetic efficiency and broad functional group compatibility

Methods

Results

Conclusion