Cycloaddition Reaction Of ?-lactam And 2,2,2-Trifluorodiazoethane

The ?-lactam ring is presented as the core structure in the class of ?-lactam antibacterial agents.The ?-lactams have also been used as key intermediates for bioactive compounds.Hence the development of efficient syntheses of ?-lactams have received much greater attention.The physicochemical and biological properties of an organic compound are profoundly modified by the incorporation of fluorinated moieties into organic molecules.Recently,2,2,2-trifluorodiazoethane has emerged as a very attractive CF3-containing synthon for the construction of fluorinated molecules featuring a CF3 structural subunit.In this thesis,we studied the cycloadditon reaction of 2,2,2-trifluorodiazoethane with ?-methylidene-?-lactams,which leads to CF3-substituted spirocyclic ?-lactam derivatives.The [3+2] cycloaddition of ?-methylidene-?-lactams with the in situ generated 2,2,2-trifluorodiazoethane was realized under very mild conditions,affording a wide range of corresponding products in high yields of up to 99%.In addition,by adding a catalytic amount of FeTPPCl,the reaction of ?-methylidene-?-lactams with 2,2,2-trifluorodiazoethane proceeded via a [2+1] cycloaddition to deliver the corresponding products in high yields(up to 92%)with good diastereoselectivies(up to 86:14).