781640-92-4Relevant academic research and scientific papers
Insertion of an overcrowded silylene into hydro- and haloboranes: A novel synthesis of silylborane derivatives and their properties
Kajiwara, Takashi,Takeda, Nobuhiro,Sasamori, Takahiro,Tokitoh, Norihiro
, p. 4723 - 4734 (2008/10/09)
Reactions of stable silylene-isocyanide complexes Tbt(Mes)SiCNAr (3a, Ar = Mes*; 3b, Ar = Tbt; 3c, Ar = Tip; Tbt = 2,4,6-tris[bis(trimethylsilyl) methyl]phenyl, Mes = mesityl, Mes* = 2,4,6-tri-tert-butylphenyl, Tip = 2,4,6-triisopropylphenyl) with boron compounds were investigated. Reactions of 3a,b with BH3·THF afforded the first stable silylborane-isocyanide complexes, Tbt(Mes)SiHBH2·CNAr (4a,b). Silylene complex 3a reacted with BH3·PPh3 as well to give the corresponding silylborane-phosphine complex Tbt(Mes)SiHBH 2·PPh3 (12). In addition, silylene 2 thermally generated from the corresponding disilene, Tbt(Mes)Si= Si(Mes)Tbt (1), gave 12 when reacted with BH3·PPh3. These results strongly suggested that the reactions of 3 with BH3·THF and BH 3·PPh3 proceeded via insertion of a silylene, Tbt-(Mes)Si: (2), into the B-H bond rather than the nucleophilic attack of the silicon atom of 3 toward the boron atom. Thermal dissociation of 4 and 12 into a base-free silylborane, Tbt(Mes)SiHBH2 (9), was evidenced by the base-exchange reactions. Furthermore, silylene 2 was found to insert into boron-halogen bonds as well as boron-hydrogen bonds. The novel reactivity of silylene 2 was applied to the syntheses of a variety of silylborane derivatives such as base-free silylboranes, silylborane-isocyanide complexes, and silylborates.
