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The New Reaction Control The Synthesis Of Chiral Phase Transfer Catalyst And Its Application,

Posted on:2006-07-26Degree:MasterType:Thesis
Country:ChinaCandidate:Y Z HuaFull Text:PDF
GTID:2191360155469101Subject:Organic Chemistry
Abstract/Summary:PDF Full Text Request
In this thesis, several novel reaction-controlled chiral phase-transfer catalysts were designed and synthesized from readily available materials, and were used in the asymmetric epoxidation of unfunctionalized olefins and chalcone. We also studied the enantioselective conjugate addition of chalcone in the presents of chiral Ni(acac)2 aminoalcohol complexes. Last, we studied the allylation of benzoylhydrazones with allyltrichlorosilane. Two new methods were developed for the allylation of C=N double bands and for the synthesis of benzohydrazide by benzoyl chloride in our studies. This thesis consists of three parts:1. The Synthesis and Applications of Several New Reaction-Controlled Chiral Phase-Transfer CatalystsFour new reaction-controlled chiral phase-transfer catalysts (heteropolytungstate I -IV) were synthesized from readily available materials: (S)-1-phenylethanamine, ferrocene, cinchonidine and Na8HPW9O34.19H2O via several steps. One of the catalysts heteropolytungstate ( I ) was characterized by IR and elemental analysis, others were characterized by IR. Heteropolytungstate ( I ) catalyzed the enantioselective epoxidation of enones with H2O2 as the oxidant. With chalcone as substrate and 0.1 mol% of catalyst, the yield up to 99% was achieved, but the enantioselective excess was low. The epoxidation experimental results show its reaction-controlled character. It can be recovered like heterogeneous catalyst but also acts as homogenous catalyst.2. The Study of Catalytic Enantioselective Michael AdditionsIn this part, we studied the applications of chiral ferrocenyl aziridino alcohol ligands with two stereogenic carbons in the catalytic enantioselective michael addition of diethylzinc reagents to a,β-unsaturated ketones. We investigated the factors thataffected the reaction, such as temperature. It has been found that the chiral catalysts L* in conjunction with Ni(acac)2 give good to high yields (36%~96%) in the enantioselective conjugate addition of a,β-unsaturated ketones with diethylzinc reagents, but the enantioselective excess was low (up to 13.4%).3. The study of Asymmetric Allylation of Benzoylhydrazones with Allyltrichlorosilane via a Chiral Pentacoordinate SilicateIn this part, our works focused on the asymmetric allylation of C=N double bonds (benzoylhydrazones) with allyltrichlorosilane under the stoichiometric amounts of (+)-DET or compound (V) (15,2S)-2-(benzo[d][l,3]dioxol-5-ylmethylamino)-l-(4-nitrophenyl)propane-l,3-diol. To our surprise, the allylation of benzoylhydrazones with allyltrichlorosilane was carried out. Though both the yields and the enantioselection of the reactions were poor, we were satisfied with that the reaction was triggered by (+)-DET or compound (V). It means that we have found a new chiral auxiliary for the asymmetric allylation of benzoylhydrazones with allyltrichlorosilane.
Keywords/Search Tags:Chirality, Asymmetry, Epoxidation, Allylation, Benzoylhydrazones, Conjugate addition, Michael addition
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