Multicomponent Reactions Based On N-Sulfonyl Ketenimine Intermediates

Multicomponent Reactions have attached much attention in recent synthetic organic methodology.An example is the chemist focus on the multicomponent reactions based on ketenimine intermediates.This dissertation reviewed the ketenimines and the multicomponent reactions they participated in,and then pay attention to the multicomponent reaction based on N-sulfonyl ketenimine intermediates,an active intermediate,thorough which can construct numerous of heterocycles and other compounds for very important application.The results and details are shown below:1.A one-pot synthesis of N-sulfonyl-2-alkylidene-1,2,3,4-tetrahydropyrimidines via a highly selective and copper-catalyzed multicomponent reaction of sulfonyl azides,terminal alkynes andα,β-unsaturated imines has been developed.We explored the protocol with a variety of terminal alkynes,sulfonylazides and imines.In all cases,the three-component reaction furnished 2-alkylidene-1,2,3,4-tetrahydropyrimidines as the major or sole products in the optimized conditions.In several cases,we also isolated the byproducts azetidin-2-imines in high trans selectivity.The formation of the byproducts was well explained by the proposed mechanism.The method is versatile,concise, general,highly selective,and very efficient.The substrates are readily available and theα,β-unsaturated imine substrates could be generated from amines andα,β-unsaturated aldehydes in a one-pot sequential process.2.Synthesis ofγ-nitro N-sulfonyl imidates via a one-pot four component reaction of terminal alkynes,sulfonyl azides,alcohols and nitroalkenes.With optimized reaction conditions,various of alkynes,azides,alcohols,and nitroalkenes are screened and the reaction showed high tolerability toward all kinds of substituents to obtain the product.There are two chiral carbons in the product molecule and the diasteromeric ratio was well determined.The diasteromeric selectivity was also discussed.The procedure is simple,the substrates are highly tolerable and the four component reaction condition is mild.