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Studies on [3+3] Cyclization of α,β-unsaturated Carbonyl Compounds

作　者: DIALLO ABOUBACAR（布巴）
导　师: 刘群
学　校: 东北师范大学
专　业: 有机化学
关键词: α,β-unsaturated carbonyls dimethyl glutaconate [3+3] cycloaddition α-oxo-ketene dithioacetals 4-(S,S-dimethylbromothio)crotonate polysubstituted arenes
分类号: O621
类　型: 博士论文
年　份: 2013年
下　载: 3次
引　用: 0次
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内容摘要

The aldehydes and ketones in basic medium give an enolate anion which acts as a nucleophilic reagent. In addition, they react with nucleophiles that are related to deficient carbon. It is therefore not surprising that in a basic medium, an aldehyde or ketone having at least one hydrogen atom in α-position reacts on itself in the absence of any other reagent. The enolate formed from a first molecule is added to the carbonyl group of another molecule. In a broader sense the carbonyl compounds for example esters, amides, carboxylates condense with aldehydes or ketones to giveβ-hydroxy-carbonyl compounds which in turn eliminate a water molecule to form α,β-unsaturated carbonyl compounds. These have been used as efficient methods in [3+3] cycloadditions. Such reactions have been widely used both in the synthesis of natural products and the synthesis of six-membered cyclic compounds. However, majority of the synthetic applications of of α,β?-unsaturated carbonyl compounds were focused on the synthesis of heterocycles like pyrroles, indoles, furans, pyrans, piperidine, pyridine, benzofurans, thiophenes and benzothiophenes.The formation of multisubstituted benzene compounds via [3+3] or [3+2+1] cycloaddition based on α,β-unsaturated carbonyls has been reported rarely. Although these approaches have contributed to the development of the synthetic pathway for the synthesis of various substituted benzenes, to our knowledge, there has been no report on the synthesis of polysubstituted benzenes from commercially available starting materials in a single step under mild conditions with the advantage of environmentally benign, atom and energy-efficient processes that do not rely on toxic/precious metals.Thus, during our research we have developed the Synthesis of polysubstituted benzene derivatives from a-oxo-ketene dithioacetals with ethyl4-(S,S-dimethylbromothio)crotonate via [3+3] cycloaddition approach under mild conditions. Although, a few synthetic approaches for the construction of this kind of cycloaddition have been reported but most of them many suffer from long sequences of reactions in several stages with lowest yields.We developed a new efficient way for the synthesis of polysubstituted benzene compounds in high yields from the sequential addition reaction of Michael, nucleophilic cyclization, condensation and oxidation followed by aromatization of α,β-unsaturated carbonyl compounds, a readily available raw material with dimethyl glutaconate, commercially available, in the presence of sodium hydroxide as catalyst under mild conditions. These benzene compounds were characterized by all spectral analysis whose data were recorded in this present work.

全文目录

Abstract  4-5
Table of contents  5-7
Acknowledgements  7-9
Chapter Ⅰ:Introduction  9-11
Bibliographic Review  11-41
  1.1. Benzannulation  11-20
    1.1.1. Synthesis of fluoranthene via [3+3] cycloaddition  11-12
    1.1.2. Synthesis of tetrahydroindolizidines and hexahydroquinolines 11  12
    1.1.3. Nucleophilic aryl and heteroaryl-methyl  12-19
    1.1.4. Other nucleophiles  19-20
  1.2. Synthesis of diaryl sulfides  20-25
    1.2.1 Brief introduction  20-21
    1.2.2. Synthesis of arene 113a  21-22
    1.2.3. Synthesis of arenes 116 and 119  22-23
    1.2.4. Synthesis of arene 122b  23-25
  1.3. Synthesis of trisubstituted benzofurans  25-27
  1.4. Benzannulation of 3-Substituted Pyrroles to Indoles  27-28
  1.5. Synthesis of polysubstituted benzene derivatives from precursors such a Nitroalkanes  28-31
    1.5.1. Synthesis of poly-substituted nitrobenzene derivatives  28-29
    1.5.2. Synthesis of symmetrical diarylamines  29-30
    1.5.3. One-pot synthesis of 3,5-alkylated acetophenone and benzoate derivatives via ananionic domino process  30-31
  1.6. Synthesis of Substituted aromatic hydrocarbon  31-33
  1.7. Synthesis of chiral tetrahydronaphthalenes  33-34
  1.8. Synthesis of calamenene sesquiterpenes  34-35
  1.9. Synthesis of six-membered carbo- and heterocyclic compounds  35-36
  1.10. Synthesis substituted aromatic amines  36-37
  1.11. Asymmetric synthesis of biaryls  37-38
  1.12. Dimerization followed by aromatization  38-39
  1.13 -Synthesis of multiply-substituted benzenes via a formal [3+3] cycloadditionapproach  39-41
ChapterⅡ:Synthesis of polysubstituted benzenes via Tandem [3+3] and [3+2+1]Annulation-Aerobic Oxidative Benzannulations  41-55
  2.1. General procedure for the synthesis of α,β-unsatured carbonyl compounds 1  41-42
  2.2. General procedure for synthesis of 3-benzylidenepentan-2,4-dione lo and ethyl 2-benzyli-dene-3-oxobutanoate 1p  42
  2.3. General procedure for the synthesis of polysubstituted benzene 3  42-43
  2.4. General procedure by one-pot synthesis of polysubstituted benzene via the [3+2+1]cycloaddition from acetophenone, aldehyde and dimethyl glutaconate  43-44
  2.5. Results and Discussion  44-47
  2.6. Conclusion  47-48
  2.7. Spectrum Data of compounds 3  48-55
Chapter Ⅲ:Synthesis of polysubstituted benzene derivatives from a-Oxo-ketenedithioacetals with ethyl 4-(S,S-dimethylbromothio)crotonate via [3+3] cycloadditionapproach  55-68
  3.1. General procedure for the synthesis of α-Oxo-ketene dithioacetal 2  55-56
  3.2. General procedure for synthesis of compounds 3  56-57
  3.3. General procedure for synthesis of reagent 4  57
  3.4. General procedure for the synthesis of benzene polysubstituted 5  57-58
  3.5. Results and Discussion  58-60
  3.6. Conclusion  60-61
  3.7. Spectrum Data of compounds 5  61-68
References  68-77
Appendix  77-112

Studies on [3+3] Cyclization of α,β-unsaturated Carbonyl Compounds

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