Reactivity of 2,6‐Dihalophenyl Lithium Reagents Towards Chlorosilanes. Synthesis and Structure of 2,3‐ and 2,6‐Dihalophenyl(di‐)silanes

The reaction of 2,6‐dihalophenyllithium 2,6‐ X 2 C 6 H 3 Li ( X = F, Cl, Br) with the chlorosilanes ClMe 2 SiSiCl 2 Me, SiCl 4 , and HSiCl 3 afforded the diaryldisilanes (2,6‐ X 2 C 6 H 3 SiMe 2 ) 2 [ X = F ( 1a ), Cl ( 1b ), Br ( 1c )] and the diaryl‐ and triarylsilanes (2,6‐ X 2 C 6 H 3 ) 2 SiCl 2 [ X = F ( 3a ), Cl ( 3a )], (2,3‐Br 2 C 6 H 3 ) 2 SiCl 2 ( 4c ), (2,6‐F 2 C 6 H 3 ) 3 SiH ( 6a ), and (2,6‐ X 2 C 6 H 3 ) 2 Si(H)Cl [ X = Cl ( 7b ), Br ( 7c )], respectively. The formation of 4c was rationalized on the basis of an equilibrium that exists between the aryllithium isomers 2,6‐Br 2 C 6 H 3 Li and 2,3‐Br 2 C 6 H 3 Li. Reduction of 3a , 3b , 4c , 7b , and 7c using LiAlH 4 provided the diarylsilanes (2,6‐ X 2 C 6 H 3 ) 2 SiH 2 [ X = F ( 2a ), Cl ( 2b ), Br ( 2c )] and (2,3‐Br 2 C 6 H 3 ) 2 SiH 2 ( 5c ), respectively. The products were characterized by multinuclear NMR spectroscopy ( 1 H, 13 C, 19 F, 29 Si) and in case of 1a , 1b , 2a , 2b , 2c , 5c , and 6a also by X‐ray crystallography.