Visible Light Induced Alkynylation Of Ethers And [2+2] Photocycloaddition Without Additional Photocatalyst

Alkynes,as a common structure in organic chemistry,can connect and transform different parts of molecular scaffolds.The carbon-carbon triple bond is one of the most important functional groups in organic chemistry,and many reactions are known to form new compounds through the conversion of alkynyl groups.The organic reaction promoted by visible light has many advantages such as mild conditions,almost no pollution to the environment,and easy handling,which lays the foundation for photocatalysis to become a new synthesis strategy.This article focuses on the realization of alkynylation and [2+2] cycloaddition under the action of visible light without the addition of a photosensitizer,as follows:1.Without the addition of photosensitizer,blue light drives bromophenylacetylene and tetrahydrofuran to achieve ?-alkynylation of ether.The conditions of the synthesis method are simple,and it can be carried out only by adding equivalent amount of potassium fluoride under light.All kinds of arylalkynyl bromide can obtain corresponding alkynylation products under this condition.The mechanism has been thoroughly explored through control experiments and free radical trapping experiments.2.In the absence of external photosensitizer,blue light drives o-ynylbenzyl malononitrile and dihydropyran to achieve intermolecular [2+2] cycloaddition.In this reaction,only two substrates need to be added in the air atmosphere,and the multi-substituted cyclobutane derivatives can be constructed with excellent regioselectivity.Various aromatic,fatty alkyne and chain allyl ethers can obtain corresponding cyclization products.The spatial configuration of the product was determined by nuclear magnetic,high resolution,single crystal and other data.