The Alkynylation Of Heterocyclic Compounds C(sp~2)-H And C(sp~3)-H Bond

Carbon-carbon triple bond widely exists in many natural compounds,bioactive compounds.The reaction of alkynylation can introduce an alkynyl group into the substrate.The alkynyl group can undergo various transformations to modify the substrate.Therefore,the synthesis of alkyne compounds and their corresponding transformations have attracted the attention of synthetic chemists.Therefore,the alkynylation of the indoles C(sp2)-H bond and the alkynylation of the cyclic ethers C(sp3)-H bond have been studied.The main contents are as follows:1.Palladium-catalyzed C2-selective alkynylation of indolesIndole derivatives are widely used for fuel,medical and pharmaceutical intermediates and indole alkyne is an important bridge for the formation of indole derivatives.The C3 position of indole compounds has higher activity than C2 position,so it is even more challenging to achieve alkynylation at the C2 position of indole.This project explored the C2-selective alkynylation of indoles using palladium as catalyst,N-pyrimidine and N-pyridine as the directing group and alkynyl bromide as alkynylation reagent.The ample substrate scope,broader functional group tolerance,gram-scale synthesis and removable directing group of this strategy allow for the access of C2 alkynylated indoles in organic synthesis.2.Alkylation of cyclic ethers C(sp3)-H bonds with alkynyl estersEther was one of the most common structural fragments and commonly found in natural biological products or some synthetic drugs.2-Alkynyl cyclic ethers was very important for building new reagents with biological activity.This study first explored the alkynylation of cyclic ethers C(sp3)-H bonds with alkynyl esters.This method did not require transition metal catalysis,and the corresponding target products can be obtained under the action of peroxide and base.The reaction conditions are mild,by this method,the 2-Alkynyl cyclic ethers can be environmentally friendly synthesized.