Formation of a Hybrid 1-Bora-3-boratabenzene Heteroarene Anion Derivative

Angew Chem Int Ed Engl. 2022 Aug 1;61(31):e202205565. doi: 10.1002/anie.202205565. Epub 2022 Jun 21.

Abstract

The B(C6 F5 )2 -substituted borole 2⋅SMe2 was obtained from the phenyl bis(trimethylsilylethynyl) borane SMe2 adduct (1⋅SMe2 ) by a synthetic sequence containing a rare 1,1-hydroboration reaction. Subsequent thermolysis at 50 °C converted it to the bicyclic borenium/borate zwitterion 3⋅SMe2 . Photolysis of 3⋅SMe2 gave the diboracyclohexadiene derivative 4⋅SMe2 , which after ligand exchange with N,N-dimesitylimidazolylidene and deprotonation gave the 1-bora-3-boratabenzene anion derivative as its potassium salt 6. Some unique follow-up reactions of the unsaturated diboron containing six-membered heterocycles were investigated.

Keywords: Boraalkene; Boraborataarene Anion; Borataalkene; Boron; Framework Rearrangement.