Quantitative syntheses of permethylated closo-1,10-R2C2B8Me8 (R = H, Me) carboranes. Egg-shaped hydrocarbons on the Frontier between inorganic and organic chemistry

Abstract

Electrophilic methylation of the closo-1,10-R₂C₂B₈H₈ (1) (R = H or Me) dicarbaboranes at higher temperatures or thermal rearrangement of the 1,6-R₂C₂B₈Me₈ (3) compounds at 400–500 °C generated the B-permethylated derivatives closo-1,10-R₂C₂B₈Me₈ (2) in quantitative (>95%) yields. The compounds exhibit extreme air stability as a consequence of a rigid, egg shaped hydrocarbon structures incorporating inner 1,10-C₂B₈ carborane core.