One-pot Synthesis Of Alkynyl Phosphonates And Researches On The Methodology

Phosphorus is not only one of the trace elements widely exist in various organisms, but also the pivotal atom of building the functional molecules. Phosphorus compounds have attracted widespread research interests due to the special electronic properties, as well the unique reaction activities in organic synthetic chemistry. Alkynyl phosphonates is one of the important phosphorus-containing alkynyl derivatives with a phosphorus atom directly connected to an unsaturated carbon-carbon triple bond. Also, alkynyl phosphonates are able to be readily transformed into diverse phosphorus-fused compounds. Therefore, the significant molecules have been extensive applied in the fields of biomedicine, organic synthesis, natural products and functional polymer materials. Thus it is still highly desired for the synthesis of the versatile compounds. Typically, transition metal-catalyzed cross-coupling methodologies were usually utilized for the formation of the phosphorus carbon (sp) bonds. However, limitations such as toxicity substrates and homo-coupling of the starting materials restricted the general applications of the protocols. Thus great contributions have been paid to develop new methods to solve the issues.Under the background, we have demonstrated a novel strategy towards arylethynyl sulfides, yamines and symmetrical dialkynyl selenides in a one-pot manner. One Pot Synthesis features for simple operation, good selectivity and high efficiency. Encouraged by the fruitful results, we put forward the practical protocol towards the alkynyl phosphonate after the extensive literature investigations.This thesis focused mainly on the synthetic methodology of alkynyl phosphonates and further probe on the reaction mechanism.Firstly, the background and significance of the research project were introduced in the 1st chapter of the thesis. Then the characteristics of the One Pot Synthesis were highlighted when compared with the traditional synthetic methods; then the research objective was established at the end of the introduction part of the thesis.Then in the 2ed chapter, preparation of the inexpensive starting materials aryl acetyl phosphonates was introduced. Aryl acetophenones was brominated with NBS towards a-bromo-aryl acetophenones. And the treatment of a-bromo-aryl acetophenones with phosphite esters afforded the corresponding substrates for the one-pot reaction, which also was known as Arbuzov reaction. Successively, reactions were carried out to obtain the optimal conditions. Induced by the strong base LiHMDS, different aryl acetyl phtosphonates were successfully transformed into phosphonated alkynes under the optimal conditions. By comparison with some traditional methods, the novel reaction becomes attractive due to high selectivity, cheap substrates, simple operation and less environmental pollution.Based on the successful isolation and further analysis of the key intermediate, the mechanism of the reaction involving the elimination procedure was proposed after the literatures research.All the compounds and intermediates were characterized by 1H NMR,13C NMR, 31P NMR, EI; all the target compounds synthesized in this thesis were characterized by 1H NMR,13C NMR,31P NMR, EI, IR, HRMS.