Silaheterocyclen, XXV. (Me₃SiO)₂SiCHCH₂tBu: Ein Siloxy‐funktionalisiertes Syntheseäquivalent für Dichlorneopentylsilaethen

Abstract

(Me3Si0)2Si=CHCH2tBu (4) is obtained by the reaction of (Me3SiO)zSi(C1)CH=CH2 (2) with LitBu. The reaction proceeds via the a-lithiated species 3, which can be intercepted by trimethylsilyl triflate to give 5. Silaethene 4 dimerizes to the E/Z-isomers of disilacyclobutane 7 and adds to Me,SiOMe to give 6. The reactivity of 4 resembles that of ClZSi=CHCH2tBu(1): A [4 + 21 cycloadduct is obtained from the reaction with anthracene, and with 1,3-cyclohexadiene and 1,3-cycloheptadiene mixtures of monosilacyclobutanes (10 and 12) and bicyclic Diels-Alder adducts (9 and 11) are available. Exclusive [2 + 21 cycloaddition reactions take place with styrene (formation of 13), 2,3-dimethyl-l,3-butadiene (--t19), and 1,3-butadiene (+21). Detaillierte Reaktivitatsstudien an Neopentylsilaethenen

The effect of substituents at silicon on the cross-metathesis of trisubstituted vinylsilanes with olefins

“…Analysis of selected products (a) MeCl 2 SiCH@CHCH 2 OC 4 H 9 , collected fraction 119-123°C/1 mmHg, isolated yield 75%; 1 H NMR (C 6 D 6 , d, ppm): 0.49 (s, 3H, SiMe), 0.79-0.90 (m, 3H, CH 3 ), 1.27-1.53 (m, 4H, CH 3 CH 2 CH 2 ), 3.15-3.23 (m, 2H, CH 3 CH 2 CH 2 CH 2 O), 3.63-3.68 (m, 2H, OCH 2 CH@), 6.06 (dt, 1H, J = 18.5 Hz, 1.9 Hz, @CHSi), 6.33 (dt, 1H, J = 18.5 Hz, 3.6 Hz, @CHCH 2 O); 13 C NMR (C 6 D 6 ): 5.4 (SiMe), 14.3 (CH 3 ), 19.9 (CH 3 CH 2 ), 32.4 (CH 3 CH 2 CH 2 ), 70.9 (CH 3 CH 2 CH 2 CH 2 O), 71.7 (OCH 2 CH@), 122.8 (@CHSi), 150.4 (@CHCH 2 O); MS: m/z (rel. intensity) of ethoxy derivative: 61 (15), 77 (32), 89 (17), 95 (11), 101 (18), 103 (17), 105 (40), 117 (10), 119 (22), 129 (11), 131 (14), 133 (100), 134 (13), 143 (11), 145 (62), 146 (10), 147 (12), 173 (11), 189 (30), 191 (11), 205 (13), 131 (11), 233 (11), 237 (15).…”

“…The chemicals (complexes II and III, decane, dodecane, CH 2 Cl 2 , C 6 D 6 , H 2 C@CHSiCl 2 Me) were obtained from Aldrich. The other substituted vinylsilanes were prepared by the literature methods, H 2 C@CHSiCl 2 -(OSiMe 3 ) [18], H 2 C@CHSiCl 2 Ph [19]. H 2 C@CHSiCl 2 -(C 6 H 4 -X-4) (where X = Me, CF 3 ) were synthesised using the same methodology as in the case of H 2 C@CHSiCl 2 Ph.…”

Silaheterocycles. 32.1 Facile Synthesis of 3-Alkoxy-1-silacyclobutanes from the Trichlorovinylsilane/t-BuLi Reagent and Vinyl Ethers

“…Thus, the reaction of 5 with 2 equiv of methyllithium yielded compound 15 , whereas the reaction with phenyl Grignard reagent gave silacyclobutane 17 . Only 2-neopentyl-1,1-bis(trimethylsiloxy)-1-silene [from chlorobis(trimethylsiloxy)vinylsilane and t- BuLi] shows reactivity similar to that of silene equivalent 1 : it reacted with isobutyl vinyl ether to give silacyclobutane 16 . Alternatively, the same compound was obtained in the reaction of 5 with LiOSiMe 3 in diethyl ether.…”

“…Solvents were dried by standard methods. Trichlorovinylsilane and chlorodimethylvinylsilane were obtained from Wacker Chemie GmbH (Burghausen, Germany); chlorodiphenylvinylsilane and chlorobis(trimethylsiloxy)vinylsilane were synthesized according to refs and . The silanes were distilled from K 2 CO 3 prior to use.…”