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

Abstract The B(C 6 F 5 ) 2 ‐substituted borole 2 ⋅SMe 2 was obtained from the phenyl bis(trimethylsilylethynyl) borane SMe 2 adduct ( 1 ⋅SMe 2 ) 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 ⋅SMe 2 . Photolysis of 3 ⋅SMe 2 gave the diboracyclohexadiene derivative 4 ⋅SMe 2 , 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.