A sterically congested aryltrimethylstannane – Synthesis, reactivity, transmetalation and CH–π interaction

The synthesis of a novel sterically congested tetraorganotin compound, (4-tert-butyl-2,6-dimesitylphenyl)trimethylstannane (1), is reported and its reactivity with special focus on transmetalation studied. The reaction of compound 1 with reagents such as HgCl2, BiCl3 and HOTf gave (4-tert-butyl-2,6-dimesitylphenyl)dimethyltin chloride (2) and (4-tert-butyl-2,6-dimesitylphenyl)dimethyltin triflate (3), respectively, as a result of selective tin–methyl bond cleavage. Less bulky aryltrimethyltin derivatives react with BiCl3 to give both tin–methyl and tin–aryl bond cleavage. Hydrolysis of compound 3 proceeds slowly to give bis-(4-tert-butyl-2,6-dimesitylphenyl)dimethyl stannoxane (5) via the intermediate (4-tert-butyl-2,6-dimesitylphenyl)dimethyltin hydroxide (4). All terphenyldimethyltin derivatives that were characterized by single crystal X-ray diffraction analysis show C–H⋯π interactions. Based on these results, the optimum C–H⋯π distance (C⋯centroidaryl distance) is suggested to be in the range 3.4 and 3.5 Å.

Graphical abstractThe transmetalation of organotin compounds such as PhSnMe3 and (4-tert-butyl-2,6-dimesitylphenyl)trimethyltin (1) with BiCl3 was studied. In contrast to PhSnMe3, the terphenyl-substituted tetraorganotin compound shows selective tin–methyl bond cleavage. The unusual reactivity of 1 also led to the isolation of (4-tert-butyl-2,6-dimesitylphenyl)dimethyltin triflate showing Sn–CH3 ⋯ π interaction.Figure optionsDownload full-size imageDownload as PowerPoint slide