Silicon-Carbon Unsaturated Compounds. 66. Photolysis of cis- and trans-1,2-Dimethyl-1,2-diphenyl-1,2-disilacyclohexane in the Presence of Isobutene

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• 作者：Mitsuo Ishikawa ; Shougo Shirai ; Akinobu Naka ; Hisayoshi Kobayashi ; Joji Ohshita ; Atsutaka Kunai ; Yohsuke Yamamoto ; Seung-Hun Cha ; Kyung Koo Lee ; and Young-Woo Kwak
• 刊名：Organometallics
• 出版年：2002
• 出版时间：September 30, 2002
• 年：2002
• 卷：21
• 期：20
• 页码：4206 - 4211
• 全文大小：107K
• 年卷期：v.21,no.20(September 30, 2002)
• ISSN：1520-6041

文摘

A mixture of cis- and trans-1,2-dimethyl-1,2-diphenyl-1,2-disilacyclohexane (1a and 1b)was prepared by the reaction of 1,4-bis(chloromethylphenylsilyl)butane with lithium metalin the presence of a catalytic amount of dimethylphenylsilyllithium in THF. The photolysisof pure 1a in the presence of isobutene afforded cis-2,3-benzo-1-isobutyl-1,4-dimethyl-4-phenyl-1,4-disilacyclooct-2-ene (2a) in 63% yield, in addition to a small amount of a formal[2 + 2] cycloadduct (3a) with cis-configuration, arising from addition of the rearranged silenewith isobutene. Similar photolysis of 1b with isobutene gave a trans-adduct (3b) formed byformal [2 + 2] cycloaddition of the rearranged silene arising from 1b to isobutene as themain product, together with a small amount of trans-2,3-benzo-1-isobutyl-1,4-dimethyl-4-phenyl-1,4-disilacyclooct-2-ene (2b). The structure of the [2 + 2] cycloadduct 3b, was verifiedby X-ray crystallography. The thermolyses of 3a and 3b at 150 C for 24 h produced 2a and2b, respectively, in quantitative yields.