Studies Based On The Donor-acceptor Cyclopropanes On Dihydrogen Naphthol And Naphthalene Synthesis Methods

Development of a general method for quickly generating structural complex organic molecules in step-and atom-econmical manners has always been a significant goal for synthetic chemistry.And the cascade reaction has been proved to one of the most powerful methods and obtains a rapid development in organic synthesis.In the first chapter of the article,we have introduced various typical types ring-opening reactions and cascade reactions of Donor-Acceptor(D-A)cyclopropanes to be the background.The presentation of second chapter provides detailed information on the D-A cyclopropanes as C3 and C4 building blocks to participate reactions,and about the Sc(OTf)3 catalyzed [4+2]-annulation reaction between electron-rich phenols and D-A cyclopropanes to synthesize of polysubstituted dihydronaphthols.At the beginning of third Chapter,it introduced the dual catalysis based on the reaction of organocatalysts in detail to be the background,then we introduced our work: the dual catalysis of 3,4,5-trimethylphenol firstly as organocatalyst with Lewis acids catalyze the D-A cyclopropanes to synthesize of naphthalene.Chapter 1: In the introduction section,we choose the architectural feature of D-A cyclopropanes as the starting point and generalize the reaction types in the past.Next,we classify and summarize various types of the ring-opening reactions and cascade reactions.It proves that D-A cyclpropanes as significant building blocks could quickly constructed complex molecules with other reagents and are worth exploring.Due to the unique advantages of highly efficient construction of complex skeletons,D-A cyclpropanes own huge potential in total synthesis.Chapter 2: Firstly,it summarized that D-A cyclpropanes as C3 and C4 building blocks to participate reactions in detail,and highlight the generalist of D-A cyclpropanes on the efficient construction of complex skeletons.Enlightened by the Friedel-Crafts reactions between electron-rich aromatic compounds and D-A cyclpropanes,we developed the ring-opening reaction between electron-rich phenols and D-A cyclpropanes through Friedel-Crafts reactions.The complete study on cascade reactions between D-A cyclpropanes and electron-rich phenols to synthesize dihydronaphthols is based on the ring-opening reaction.It improve the problems in synthesizing the dihydronaphthols.Chapter 3: Based on the summary of dual catalysis examples about organocatalyst,the specific cases prove that dual catalysis by different catalysis’ s complementary advantages will provide more room and new ideas for the solution to some challenging problems.Based on the previous work,the 3,4,5-trimethylphenol could be new type organocatalyst in cascade reactions.It is verified that the leaving group 3,4,5-trimethylphenol as nucleophilic reagent attacks the activated D-A cyclopropanes by Lewis Acids achieving the ring-opening reaction.Finally,the cascade reaction synthesize naphthalene with 3,4,5-trimethylphenol leaving.It is first time study about this new type organocatalyst and the catalytic mechanism is still in the further study.