Synthesis Of Oxindole Derivatives Via DABCO Catalyzed Domino Reactions Based On Allenoates

In recent years,various cyclic compounds have been constructed based on the oxindoles,such as indol-fused heterocyclic compounds,spirooxindole compounds,which are hot topic in organic synthetic chemistry.Among them,spirooxindole compounds,which are broad in nature products and have promising activities in various therapeutic areas,becoming a privileged skeleton for drug discovery.Therefore,the reaction of constructing spirooxindole derivates based on the C3 unsaturated oxindoles,tertiary anmine as a catalyst,has attracted a wide range of attention.Oxindoles derivatives with a few reaction sites have been designed by conjugating diene compounds on isatin C3 position,which are lively interaction esters of 2,3-butadiene in the presence of DABCO after effective control and regulation,to construct an important molecular skeleton.1.Oxindole derivatives I-1a with multiple reactive sites based on Isatin have been designed,which were lively interaction esters of 2,3-butadiene through [3+2] domino reactions in the presence of DABCO,and allene as C2 synthons.Firstly,furnishing 2,3,5-substituted tetrahydrofuran furan derivatives with oxindole moieties and two exocyclic double bonds in high yield,which was the efficient method for the construction of 2,3,5-substituted tetrahydrofuran furan derivatives in high yields and stereoselectivity.2.Through changing the oxindole derivatives reaction sites,a new oxindoles derivatives II-1a were designed,which could construct three new products: pyrano[2,3-b]indol,dihydropyrano[2,3-b]indol with E or Z exocyclic double bond through controlling the reaction conditions.This was a [4+2] domino reaction,and allene aiso as C2 synthons.It was not only a simple and efficient synthetic method for the synthesis of indol-fused heterocyclic compounds,but aslo could control the different reaction conditions to the structure and configuration of the substrate.3.The new oxindole derivatives III-1a was obtained by regulating the substituents on the nitrogen atom,which was used to synthesize a new class of spirooxindole compound in the presence of DABCO,with the mild reaction conditions,high yield,good selectivity,wide adaptability.It was worth noting that this was novel reaction with unsubstituted esters of 2,3-butadiene as a C4 synthon in the catalytic reaction of amines.