A Pyridine-Stabilized N-Phosphinoamidinato N-Heterocyclic Carbene-Diboravinyl Cation: Boron Analogue of Vinyl Cation

Jun Fan; Pei-Ting Chia; Zheng-Feng Zhang; Ming-Chung Yang; Ming-Der Su; Cheuk-Wai So

doi:10.1002/anie.202212842

A Pyridine-Stabilized N-Phosphinoamidinato N-Heterocyclic Carbene-Diboravinyl Cation: Boron Analogue of Vinyl Cation

Angew Chem Int Ed Engl. 2022 Nov 14;61(46):e202212842. doi: 10.1002/anie.202212842. Epub 2022 Oct 17.

Authors

Jun Fan¹, Pei-Ting Chia¹, Zheng-Feng Zhang², Ming-Chung Yang², Ming-Der Su^{2

3}, Cheuk-Wai So¹

Affiliations

¹ School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, 637371, Singapore.
² Department of Applied Chemistry, National Chiayi University, Chiayi, 60004, Taiwan.
³ Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.

PMID: 36098906
DOI: 10.1002/anie.202212842

Abstract

A boron analogue of vinyl cation, pyridine-stabilized N-phosphinoamidinato N-heterocyclic carbene (NHC)-diboravinyl cation 2⁺ , was synthesized by displacement of bromide in diborene 1 with excess pyridine. Experimental and computational studies showed that the positive charge is mainly at the B-B skeleton with delocalization to the pyridine ligand. One of the main modes of reactivity is through the B=B double bond alongside activation of the pyridine substituent, where the B_pyridine center is the predominant nucleophilic center and the predominant electrophilic center is either the activated pyridine para position or the B_NHC center, illustrating the presence of diborene cation A, borylene-borenium cation B and diborene-pyridinium cation C resonance structures in cation 2⁺ .

Keywords: Boron; Diborene; Small Molecule Activation; Vinyl Cation.

Abstract

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