Studies On Reactions Related To Functionalized Isocyanides Or Arynes

Owing to their unique structure and properties,functionalized isocyanides and arynes have been widely used in the exploration of new reactions,thus providing a new pathway for the development of new reactions and new methodologies in organic synthesis.This thesis designs a new functionalized isocyanide3-?2-isocyanophenyloxy?acrylate,which can react with common isocyanide and aryne.Furthermore,anorganophosphine-catalyzedreactionof3-?2-isocyanophenoxy?acrylate to form 3-?benzoxazol-2-yl?acrylate is also described.On the other hand,regioselective insertion/arylation and double insertion of aryne with 3-methyleneoxindole has also been examined.The results of this thesis expand the application of functionalized isocyanides and arynes.This thesis consists of the following parts:Part 1,A novel?5+1?annulation reaction of functionalized3-?2-isocyanophenoxy?acrylate and aromatic,aliphatic isocyanides toward many?Z?-2H-benzo[b][1,4]oxazin-2-one derivatives has been investigated.This domino reaction involves the unusual heterodimerization of two different isocyanides and the in situ C-N bond cleavage of the isocyano group,which represents a novel reactivity profile of isocyanide.The whole transformation involves the cleavage and the formation of multiple C-O,C-C,and C-N bonds,which demonstrates high synthetic efficiency.The advantages of this strategy include broad substrate scope,excellent atom economy and stereoselectivity.Part 2,An organophosphine-catalyzed reaction of 3-?2-isocyanophenoxy?acrylate to form 3-?benzoxazol-2-yl?acrylate has been disclosed.This reaction proceeds under mild conditions in the absence of any metal and strong base.This protocol also demonstrates broad substrate scope and excellent atom economy.Further control reaction indicates an intermolecular mechanism is responsible for this conversion.In addition,in the presence of excess amount of H₂O,benzoxazoles are obtained.Part 3,An unusual domino reaction of 3-?2-isocyanophenyloxy?acrylate and aryne has been examined,which enables the quick aryne vicinal difunctionalization by the installation of a benzoxazole and an olefin.This cascade reaction provides a new reactivity mode for both isocyanide and aryne chemistry.Moreover,the unique structure of the resultant products also enables further olefination via the rhodium-catalyzed C-H activation.This procedure also features absence of any catalyst and wide substrate scope.Part 4,Selecetive insertion/arylation and double insertion of aryne with3-methyleneoxindole to approach structurally complex ortho-difunctionalization arene has been disclosed.Regioselecetive insertion/arylation of aryne with3-methyleneoxindole proceeds smoothly to generate 3,3-diarylated oxindoles in acetone under 60°C.Interestingly,an unprecedented double insertion of aryne into C-C?bond of 3-methyleneoxindole in THF under 120°C is reported,thus providing a quick access to dibenzo[b,e]azepin-6-ones derivatives.This methodology represents an environmentally benign protocol without the use of any metal and also distinguished by high efficiency,simple operation,and broad substrate scope.