| In this dissertation, the tandem reactions of bromoallenes with 1, 3-dicarbonyl compounds in the presence of a base; the Cp2TiCl-mediated intramolecular radiacl cyclization of epoxy-allenes; and the silylcupration of alkynylphosphine oxides were investigated.Firstly, the tandem addition-cyclization of bromoallenes with 1, 3-dicarbonyl compounds was investigated. (1) the tandem addition-cyclization of dimethyl malonate with mono- or diarylsubstituted bromoallenes in the presence of NaH to give corresponding (E)-dimethyl arylmethylidenecyclopropane-1, 1-dicarboxylates; however, the reaction with alkylsubstituted bromoallenes proceeded in a Sn2' manner to give acetylenic esters. (2) the tandem addition-cyclization of 1, 3-diketones with monosubstituted bromoallenes in the presence of K2CO3 to give corresponding 2, 3, 4-trisubstituted furans. These results are the first present of intermolecular cyclization about bromoallenes used as allyl dication equivalents.Secondly, the Cp2TiCl-mediated radical cyclization of epoxy-allenes was investigated. The carbon radical generated from epoxide group in the presence of Cp2TiCl attack allenyl group in a highly regioselectively 5-exo mode to cyclize and to give synthetically useful 3-vinyl-4-hydroxymethane-tetrahydrofunan compounds. The reaction provided a new and efficient method for synthesis of this kind of compounds. The method has the advantages of available materials. simple manipulation. Also this method could be extended to synthesize polyfunctional five-membered carbon or nitrogen cycles.Thirdly, silylcupration of alkynylphosphine oxides was investigated. This reaction could efficiently synthesis ofβ-silylsubstituted vinylphosphine oxides with high stereo-and regioselectivity. The key vinylcopper intermediate stabilized by the diphenylphosphine oxide react with electrophiles, such as I2, PhSeBr. PhTeI and allyl bromide to giveβ-silyl-α-functionalized vinylphosphine oxides and 1, 4-dienes.
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