Formation of 1,4-Disilyl-2-butenes from Vinyl Grignard Reagent and Chlorosilanes Catalyzed by a Titanocene Complex

Abstract

Symmetrical 1,4-disilyl-2-butenes 1 have been prepared by the reaction of vinyl Grignard reagent with chlorosilanes. This reaction proceeds efficiently in the presence of a catalytic amount of titanocene dichloride at 0 degrees C in THF. When dichlorodiphenylsilane was used, 1,1-diphenyl-1-silacyclo-3-pentene 2 was obtained in a good yield.

Effects of Silyl Substituents on the Palladium‐Catalyzed Asymmetric Synthesis of Axially Chiral (Allenylmethyl)silanes and Their SE2′ Chirality Transfer Reactions

“…Tetrahydrofuran and hexane (homogenized with tetraglyme) were distilled from benzophenoneketyl under an atmosphere of nitrogen prior to use. The second generation Grubbs catalyst, [14] 1,4-disilyl-2-butenes (6a-c), [13] 3-bromo-5-trimethylsilylpenta-1,3-diene (1a), [12] [PdCl(π-allyl)] 2 , [20] dpbp, [15] Pd(dba) 2 , [21] (R)-segphos, [16] (S)-tBu-segphos, [17] tBuCH-(OMe) 2 , [22] and (MeO) 2 CHCH 2 CH(CO 2 Me) 2 [23] were prepared as reported. All other chemicals were obtained from commercial sources and used without additional purification.…”

“…[13] The whole sequence is applicable to the preparation of the triethylsilyl and dimethylphenylsilyl analogues, and compounds 1b and 1c were prepared in 59 and 48 % yield, respectively (Scheme 2, top).…”

“…5, 7.3, 18.8, 115.1, 123.6, 132.8, 136. 7.35-7.39 (m, 3 H), 7.51-7.54 (m, 2 H) ppm. 13 C NMR (101 MHz, CDCl 3 ): δ = -2.8, 22.9, 115.6, 124.5, 128.0, 129.4, 132.0, 133.6, 136.1, 138. 11.4, 16.4, 18.7, 115.3, 123.9, 133.4, 136 Palladium-Catalyzed Synthesis of (Allenylmethyl)silanes 3: Preparation of racemic (allenylmethyl)silanes 3 was conducted according to a reported procedure. [7] The reaction conditions and results are summarized in Table 1.…”

“…7.4, 12.7, 19.8, 36.2, 52.5, 52.6, 54.0, 84.5, 87.4, 172.38, 172.45, 206.3 -3.32, -3.25, 17.2, 19.8, 36.2, 52.5, 52.6, 54.0, 84.8, 86.9, 127.9, 129.1, 133.7, 138.5, 172.3, 172.4, 206.6 13 C NMR (101 MHz, CDCl 3 ): δ = -1.9, 14.1 (unresolved diastereotopic -CO 2 CH 2 CH 3 ), 17.6, 36.7, 61.6, 61.7, 63.0, 85.0, 87.2, 127.5, 128.1, 128.4, 136.7, 170.3, 170.4, 206.3 1.25 (t,J = 7.1 Hz,3 H),2 H),4 H),2 H),3 H), (m, 2 H) ppm. 13 C NMR (101 MHz, CDCl 3 ): δ = 3.2, 7.4, 12.5, 14.1 (unresolved diastereotopic -CO 2 CH 2 CH 3 ), 36.5, 61.61, 61.64, 62.9, 85.0, 87.3, 127.5, 128.1, 128.4, 136.7, 170.3, 170.4, 206 17-4.25 (m, 4 H), 4.91-4.97 (m, 2 H), 7.25-7.40 (m, 8 H), 7.46-7.49 (m, 2 H) ppm. 13 C NMR (101 MHz, CDCl 3 ): δ = -3.4, -3.3, 14.1 (unresolved diastereotopic -CO 2 CH 2 CH 3 ), 16.8, 36.5, 61.6, 61.7, 62.9, 85.3, 86.8, 127.5, 127.8, 128.1, 128.4, 129.1, 133.7, 136.7, 138.5, 170.3, 170.4, 206.5 16-4.28 (m, 4 H), 4.90-5.03 (m, 2 H), 7.25-7.34 (m, 3 H), 7.41-7.43 (m, 2 H) ppm.…”

“…13 C NMR (101 MHz, CDCl 3 ): δ = 3.2, 7.4, 12.5, 14.1 (unresolved diastereotopic -CO 2 CH 2 CH 3 ), 36.5, 61.61, 61.64, 62.9, 85.0, 87.3, 127.5, 128.1, 128.4, 136.7, 170.3, 170.4, 206 17-4.25 (m, 4 H), 4.91-4.97 (m, 2 H), 7.25-7.40 (m, 8 H), 7.46-7.49 (m, 2 H) ppm. 13 C NMR (101 MHz, CDCl 3 ): δ = -3.4, -3.3, 14.1 (unresolved diastereotopic -CO 2 CH 2 CH 3 ), 16.8, 36.5, 61.6, 61.7, 62.9, 85.3, 86.8, 127.5, 127.8, 128.1, 128.4, 129.1, 133.7, 136.7, 138.5, 170.3, 170.4, 206.5 16-4.28 (m, 4 H), 4.90-5.03 (m, 2 H), 7.25-7.34 (m, 3 H), 7.41-7.43 (m, 2 H) ppm. 13 C NMR (101 MHz, CDCl 3 ): δ = 10.3, 11.0, 14.1 (unresolved diastereotopic -CO 2 CH 2 CH 3 ), 18.8 (unresolved diastereotopic -SiCHMe 2 ), 36.…”