The Application Of Lipase Catalytic Promiscuity In The Oxidation Reaction And Multi-component Reaction

Lipase is a kind of enzyme with multiple catalytic capabilities,it has some characters such as non-toxicity,mild reaction conditions,strong catalytic ability and different activities depending on different reaction systems.This paper mainly focuses on the oxidation and multi-component reaction catalyzed by lipase,which provides an environmentally friendly and efficient way for organic synthesis.Lipase exhibits good catalytic properties in many reactions(Aldol reaction,Morita-Bayis-Hillman reaction,Mannich reaction,Knoevenagel reaction,Henry reaction,Markovnikov reaction,Michael reaction,Hantzsch reaction and so on).In some previous studies,it has been proved that lipase can mediate the in situ formation of peracids by perhydrolysis of carboxylic acids or esters,then the peracids can be used in epoxidation of olefins,Bayer-Villiger reaction and other oxidations.In this thesis,we investigated a novel lipase-mediated method for Dakin reaction.At room temperature,Novozym435 mediated the oxidation of hydroxybenzaldehyde to produce corresponding phenolic compounds.The yields were as high as 90%-97%.Novozym435 could be reused for more than 10 times and the enzyme activity did not decrease significantly.This study also provides a new idea for green Dakin reaction.In recent years,enzymatic multicomponent reactions(MCRs)have become one of the hotspots in organic chemistry.With the development of enzyme catalytic promiscuity,many complex compounds can be synthesized by enzymatic MCRs.These scientific studies have greatly broadened the application of enzymes in multi-component reactions.We have studied the application of lipase catalytic promiscuity in the synthesis of dihydropyran[4,3-b]pyran via three-component reactions.PPL catalyzed the reaction of benzaldehyde,propylene nitrile and 4-hydroxy-6-methyl-2H-pyran-2-one to form dihydropyran[4,3-b]pyran compound at 60 ~oC.The yields were 80.8%-96.8%under the mild reaction conditions.Compared with chemical catalysis,lipase catalysis is milder and more efficient.