Electrochemical Allylation Of Carbonyl Compounds In Aqueous Electrolyte Catalyzed By Zinc

Carbonyl allylation is a highly important synthetic transformation in organic and pharmaceutical chemistry. The introduction of allylic groups into carbonyl compounds has been achieved by using allylic organometallics in organic solvent. Organic reactions in water have been widely studied in order to minimize the use of organic solvent, many of which are flammable, toxic, or carcinogenic. Within the past two decades, extensive research has been carried out on developing the aqueous medium Barbier-Grignard-type reactions. Various metals, such as Zn, Sn and In, have been found to be effective in mediating such a reaction.Electrochemical methods in organic synthesis are another approach to green chemistry, because they can fundamentally eliminate the waste treatment and disposal of used redox reagent. Electrosynthesis has been proven to be an efficient method for the preparation of organometallics compounds. Especially, generating allylic organometallics by sacrificial anodes such as magnesium, aluminum and zinc, presents a useful alternative to purely chemical synthesis in the preparation of nucleophilic intermediates. However, whether in the traditional conditions or through the use of sacrificial anodes in the electrochemical conditions, the metal consumption was at least 1 equivalent or more, bringing a lot of waste of resources.In this thesis, the metal (Zn, Mg, Sn, Zn, Ga, Fe and Mn) mediated allylation reaction of carbonyl compounds in water and the electrochemical allylation reaction of carbonyl compounds were reviewed.And studies on the electrochemical allylation of carbonyl compounds in water solution were reported. Extensive studies were directed to the optimization of the reaction conditions on electrolyte, the concentration of electrolyte, current, metals for cathode. The studies have shown that with zinc foil as cathode, platinum foil as anode, and constant current (30 mA), anolyte (10 mL 0.275M LiC104), catholyte (NH4C1 (0.1 M):THF= 5 mL:5 mL) as solvent, aldehyde and ketone could be allylated with allyl bromide to achieve good to excellent yields. And catalytic amount of zinc was consumed at 25% only.