7,7‐Bis(1,1‐dimethylethyl)‐7‐silabicyclo[4.1.0]heptane

[130451-35-3] C14H28Si (MW 224.46) InChI = 1S/C14H28Si/c1-13(2,3)15(14(4,5)6)11-9-7-8-10-12(11)15/h11-12H,7-10H2,1-6H3 InChIKey = GPLNMQGTZICJEB-UHFFFAOYSA-N (reagent used as di-tert-butylsilylene donor for silylene transfer, silacyclopropane, and silacyclopropene formation) Physical Data: mp 26–28 °C; bp 35–40 °C/0.008 mm Hg;1 100–110 °C/0.05 mm Hg;2, 3 UV λmax (hexane) 226 nm (ɛ = 3.73 × 102);4 IR (neat) 2091 cm−;1 [ν(SiH)].5 Form Supplied in: not commercially available; clear colorless oil or solid. Analysis of Reagent Purity: 1H NMR (500 MHz, C6D6) δ 1.87 (m, 2H), 1.74 (m, 4H), 1.56 (m, 2H), 1.20 (br s, 10H), 1.04 (br s, 10H); 13C NMR (125 MHz, C6D6) δ 31.9, 30.3, 23.5, 19.9, 19.0, 18.5, 12.9;2, 3 29Si NMR (99.3 Hz, C6D6) δ −54.6.1, 2, 4 Preparative Methods: although photolysis of hexa-tert-butyl- cyclotrisilane in the presence of cyclohexene has been reported1 to generate the title reagent, 7,7-bis(1,1-dimethylethyl)-7-silabicyclo[4.1.0]heptane is best synthesized in the laboratory from di-tert-butyldichlorosilane by reduction with lithium (eq 1).2-4 To a cooled (−78 °C) slurry of lithium and sodium powder (6.0 g, 844 mmol Li0, 1.80 g, 78.3 mmol Na0, obtained by washing 20.0 g of a 30% lithium dispersion and 6.0 g of a 30–35% sodium dispersion in paraffin with 5 × 50 mL of hexanes) in THF (88.0 mL) is added cyclohexene (86.0 mL, 844 mmol) and di-tert-butyldichlorosilane (53.0 mL, 249 mmol). After the slurry is allowed to warm to 25 °C over 36 h, the reaction mixture is concentrated in vacuo, and the resulting residue is extracted with hexanes (5 × 50 mL). The supernatant is filtered through a short column of Celite under nitrogen and concentrated in vacuo to give the crude product as a light yellow oil.3 (1) Purification: by bulb-to-bulb distillation (100–110 °C/0.05 mm Hg).2, 3 Handling, Storage, and Precautions: air-sensitive, store under nitrogen atmosphere.