Study on the Solvent-free for Allylation Reactions of Carbonyl Compounds and Prins Cyclization Mediated by Magnesium Powder
|School||Northwest Normal University|
|Keywords||Allylation Carbonyl compounds Prins Cyclization Magnesium Cyclization Organic Synthesis Solvent-free conditions Aromatic aldehydes Solvent-free reaction phenyl Alicyclic ketones Environmentally friendly synthesis Allyl bromide Allylhalide NMR Lewis acid Stereoselectivity The organometallic reagent High allyl alcohol|
In recent years, society sustainable development and relating problems on ecology, environment, resources, economy and so on have ever increasing been a hot topic in the international society and have been elevated to a height of development strategy. So green chemistry have arrived at rapid development, environmentally friendly-economics have become an important impetus of technology innovator, and it was serious challenge of traditional organic synthesis, and make green organic synthesis gained a good development chance. Green chemistry is that apply the chemical techniques and methods to reduce or eliminate the use and generation of harmful materials, catalysts, solvents and reagents, the product, by-products those on human health, social security, ecological environment.Being important building blocks and versatile synthons, homoallylic alcohols are highly featured in the organic syntheses of many biological active molecules such as macrolides, polyhydroxylated natural products, and polyether antibiotics. Among the existing means to construct these synthetically and biologically important molecules, metal-mediated homoallylation is one of the easiest and most convenient. From the view of environmentally friendly, this thesis achieved the solvent-free synthesis of homoallylic alcohols through magnesium powder mediated Barbier-Type reaction.This thesis includes three chapters:Chapter one: Recent Development of Carbonyl AllylationThis chapter summarized the recent progress in the major methodologies of carbonyl allylation, which is one of the most fundamental transformations in organic synthesis. Specifically depict and reviewed the different solvents, solvent-free, electrochemistry, photochemistry, liquid carbon dioxide, microwave, and Prins cyclization of variety of carbonyl allylation..Chapter two: Study on Environmentally Friendly Reaction of Carbonyl Compounds and Allylbromide Mediated by Magnesium Powder. This chapter summarized Barbier-Type reaction of aldehydes and allylbromide mediated by magnesium powder under solvent-free conditions. The synthesis of homoallylic alcohols can be achieved environmentally friendly through magnesium powder mediated allylation of carbonyl compounds without side reactions which detected by 1~H-NMR. Compared to literature methods, the advantages of our methodology are moderate reaction conditions, shorter reaction time, higher yield and broader substrate scope:our methods are applicable to both aliphatic and aromatic carbonyl compounds. This is the excellent method for synthesis homoallylic alcohols environmentally friendly under solvent-free conditions.Chapter three: Study on Environmentally Friendly Reaction of Prins Cyclization' dissertation">Cyclization:One-pot Synthesis of Symmetrical 4-fluorotetrahydropyransThis chapter summarized Prins cyclization reaction of aldehydes and allylbromide mediated by magnesium powder under solvent-free conditions. The synthesis of 2,4,6-trisubstituted trahydropyran can be achieved environmentally friendly through magnesium powder mediated. This method has the following advantages: (a) The reaction has a very good stereoselectivity and chemicalselectivity; (b) easy to handle; (c) shorter reaction time and under solvent-free conditions. This is the excellent method for synthesis 2,4,6 - trisubstituted tetrahydropyran environmentally friendly under solvent-free conditions.