Synthesis and crystal structures of boryl ortho-silylaryl tri-fluoro-methane-sulfonates

Abstract

We report the synthesis and structural characterization of three crystalline borylated ortho-silylaryl tri-fluoro-methane-sulfonates: 5-(4,4,5,5-tetra-methyl-1,3,2-dioxaborolan-2-yl)-2-(tri-methyl-sil-yl)phenyl tri-fluoro-methane-sulfonate, C₁₆H₂₄BF₃O₅SSi (1a), 4-(4,4,5,5-tetra-methyl-1,3,2-dioxaborolan-2-yl)-2-(tri-methyl-sil-yl)phenyl tri-fluoro-methane-sulfonate, C₁₆H₂₄BF₃O₅SSi (1b), and 2-methyl-4-(4,4,5,5-tetra-methyl-1,3,2-dioxaborolan-2-yl)-6-(tri-methyl-silyl)phen-yl tri-fluoro-methane-sulfonate, C₁₇H₂₆BF₃O₅SSi (2), which are versatile aryne precursors. For all three compounds, the heteroatom substituents are almost coplanar with the central aromatic moiety. C-heteroatom bonding metrics are unexceptional and fall withing the typical range of C-B, C-Si, and C-O single bonds. Despite numerous electronegative sites, only weak inter-molecular inter-actions are observed in the solid state.

Keywords: aryne precursor; crystal structure; pinacole borane; solid-state structure.