Synthesis Of Carbonyl Flavor Compounds

Flavors consist of crude flavors and artificial flavors.Owing to the limit of natural conditions and process,the variety and the quality of crude flavors are limited.Artificial flavors can not only settle the shortage of crude flavor,but also can reduce the cost;moreover,some particular artificial flavors can make up the limitation of the scent of crude flavors which was induced by processing.These having carbonyl group compounds such as aldehydes,ketones and carboxylic acids which are flavors are widely used,especially in daily and edible essence.The studies of TEMPO-catalysed oxidation of alcohols and the studies of the synthesis ofα,β-unsaturated ketones by allylic oxidation in recent years were summarized,respectively.The synthesis of aldehydes, ketones and oxocarboxylic acids were completed by oxidation in the thesis.1.The oxidation of alcohols by H₂O₂/CuI/TEMPO system was described.The reaction conditions for effects on yields and the scope of H₂O₂/CuI/TEMPO system were investigated,and the proposal mechanism was speculated.It was discovered that benzyl alcohols,allylic alcohols and secondary alcohols could be selectively oxidized to corresponding aldehydes and ketones with high yields by H₂O₂/CuI/TEMPO system in CH₂Cl₂-H₂O.The structures of the products were identified by NMR and MS.2.4(5)-oxocarboxylic acids were synthesized fromγ(δ)-Lactones by NaClO and NBS respectively.Reaction conditions for effects on yields were investigated,good yields of 4(5)-oxocarboxylic acids were obtained, and the structures of the products were identified by NMR and MS.3.VO(acac)₂-Catalysed allylic and benzylic oxidation for the synthesis ofα,β-unsaturated ketones by t-BuOOH was described.The reaction conditions for effects on yields and the scope of this system were investigated,and the proposal mechanism was speculated.Moderate to excellent yields ofα,β-unsaturated ketones were obtained,and the structures were identified by NMR and MS.