Study On Synthesis Of Allenes By Ruthenium(Ⅱ) Catalyzed By 1,6-enyne Metathesis Reaction

The metathesis reaction of unsaturated compounds is a very important type of reaction.In 2005,Yves Chauvin,Robert H.Grubbs and Richard R.Schrock were awarded the Nobel Prize in Chemistry for their prominent contributions in the field of metathesis reactions.Over the past several decades,important research results have been achieved in the study of metathesis reactions.Recently,the enynes metathesis reactioon has attracted a great deal of attention.However,there are still important challenges in this field.For example,the metathesis reaction of an enyne is limited to an intramolecular reaction,and it is difficult to carry out an intermolecular metathesis reaction;the resulting product often is a 1,3-diene compound,and it is difficult to form other types of product.Allenes are a class of compounds containing cumulative carbon-carbon double bonds and have great application in natural product synthesis,medicinal chemistry and materials science.With the development of new catalytic systems and more ligands available today,the synthesis of allenes has made great progress.However,it is of great significance to develop the novel method to access alene derivarives for the reason of chalenge we are facing.In this paper,we have developed a new method for preparing allenes through intermolecular metathesis reaction of enynes.Firstly,we focus on the screening of raction conditions and ruthenium source to access the allenes derivatives.Then,we systematically optimized the solvents,additives and temperature to find the best reaction conditions.Afterly,a wide range of substrates was tested to prove the excellent applicability of present protocol.Finally,we explain the reaction mechanism in detail,and propose a conversion pathway for the preparation of allenes through enynes metathesis reaction.The method developed by this subject has many advantages,which are listed as follows: 1)Constructing allenes skeleton by metathesis reaction.In the reported literature,the rearrangement reaction or elimination reaction is often used to prepare the allenes skeleton;2)the metathesis reaction of the enynes are extended from intramolecular to intermolecular,which solve the problem that the intermolecular metathesis reaction cannot be performed;3)A variety of different functional groups are introduced into the allenes molecule,and the allenes molecule synthesized in the subject contain another carbon-carbon double bond and a bicyclic substituent;4)The method is environmentally friendly in atom economic fashion.Based on the experimental method developed in this project,it will be quite possible to make great achievement in the enyne metathesis reaction,and also make our own contribution to the development of metathesis reactions.