Study On The Reaction Of Propargylic Alcohols In The Construction Of 4-Phosphates-2H-Chromene And Derivatives

The tandem cyclization of propargylic alcohols has attracted much attentions in organic synthesis because of its excellent functional group compatibility,mild reaction conditions,high atomic economy and high chemselectivity.It has become one of the most concise and effective strategy to construct carbocycles and heterocycles.At present,various important functionalized carbon-,oxygen-and nitrogen-containing heterocyclic compounds have been successfully constructed by this strategy.2H-chromenes are very important skeletons in oxygen-containing heterocyclic compounds,which are widely found in many natural products and bioactive molecules.In medicine,material science and so on,2H-chromenes have shown a wide range of applications and development prospects in mdeicine and pestciside chemistry.Such compounds have also important application in material science and dye industry.On the other hand,organophosphorus compounds are important class of organic compounds and intermediates in organic synthesis.These compounds have excellent catalytic activity,optical activity and biological activity,which make them widely used in biological,optical active materials and medicine.Based on the wide application of 2H-chromenes derivatives and organophosphates in the fields of organic synthesis,pharmaceutical chemistry and materials science,it is particularly important to develop an atom-economical,efficient and green synthesis strategy to construct 2H-chromen-4-yl phosphinates/phosphonates.On the basis of previous works,a series of organo（thio）phosphates2H-chromenes and allenes were synthesized by tandem reaction of propargylic alcohols.The thesis includes the following three aspects:1.A series of 2H-chromen-4-yl phosphinates were constructed by tandem cyclization of 2-propynolphenols with diaryl phosphinic acids.This approach avoids the use of air-sensitive and activated reagents,and achieves the formation of2H-chromen-4-yl phosphinates without additional nucleophiles and acid promoters.Moreove,the desired products were obtained in moderate to excellent yield with good functional group compatibility and gram-scale applicity.2.Furthermore,diphenyl or dibenzyl phosphates[（RO）₂P（O）OH)]were also used as nucleophiles and acid-promoter to construct succesfully the corresponding2H-chromen-4-yl phosphonates under the similar conditions.This method has the advantages of simple operation,green and high atom-ecomony.The reaction was achieved by using（RO）₂P（O）OH as acid-promoter,but also as the nucleophile attact to allenic carbocation intermediate,and followed by cyclization.3.On the basis of our previous works,a series of tetra-substituted allenylorganothiophosphates were constructed by direct transformation of propargylic alcohols with（Et O）₂P（O）SH.The reaction was carried out with（Et O）₂P（O）SH as nucleophilie and acid-promoter under mild conditions.And additional ligands or additives and other acid catalysts were not needed for this transformation.Moreover,our developed method can further perform the gram-scale experiment with good yield and tolorate the good functional groups and substrate compatibility,which provides an efficient synthesis strategy for the synthesis of natural products or bioactive molecules containing alleneyl or thiophosphates skeletons.