Reactions Of Donor-acceptor(D-A) Cyclopropanes With 1,3-Cyclodiones

D-A cyclopropane had been widely used in syntheses of natural products and biologically active substances due to its unique reaction activity.A high polarization of the C-C bond between the donor-and acceptor-substituted carbon atoms of the cyclopropane was induced by push–pull effect,which allows for a multitude of different reactions by considering as 1,3-dipolar zwitterionic synthons.1,3-Cyclodiones can be used as both C-and O-nucleophiles because they can easily isomerize to the corresponding enols.When the subject of "The ring-opening reaction of D-A cyclopropane and 1,3-cyclodione" were explored,and it was found that under the catalysis of scandium trifluoromethanesulfonate,1,3-cyclodione participated in the reaction through Oselective nucleophilic attack and the ring opening of D-A cyclopropane were realized.The O-ring-opening product 1,3-cyclodione enol ether derivatives were obtained,which were further catalyzed by DBU(1,8-diazabicyclo[5.4.0]-undec-7-ene)to give a new type of 1-asymmetric D-A cyclopropane with a cyclic enone motif after undergoing an interesting intramolecular conversion.During the reaction,the asymmetric O-opening reaction of D-A cyclopropane with 1,3-cyclodione were also investaged.In addition,the relative stereochemical configuration of the molecular transformation products were characterized by 2D NMR experiments(Cosy,HSQC and NOESY).The types of reaction of D-A cyclopropane were enriched in topic,and the synthetic final product cyclopropane 1-(3-cycloenone)-1-ester derivative can be used for further conversion.When it comes to domino reactions and multi-component reactions,the compounds containing this structure can play a very important role in the reaction process.