Study On NaHBEt₃-catalyzed 1,3-diborylation Of Conjugated Enynes

Organic boron esters have the advantages of non-toxicity,high stability and excellent compatibility of functional groups.They are widely used in the fields of total synthesis,drug development and material science,and they are also the key structural units of chemical sensor development and many bioactive natural compounds.In addition,as one of the most commonly used functional groups in modern organic synthesis,organic boron ester functional groups are widely used in the synthesis of C–C and C–X（x = N,O,F,Br,etc.）chemical bonds.Therefore,the synthesis of organoboron esters is an important research topic in synthetic chemistry.As an important part of simple and accurate synthesis of complex molecules,polyborate compounds are of great significance in both organic synthesis and industrial production,and have attracted more and more attention.Hydroboronization is a kind of reaction that adds hydroboron bond to unsaturated bond,and it is one of the main methods to construct C-B bond.This reaction has the advantages of good selectivity,easily available raw materials and high atomic utilization rate,so it has attracted the attention of many scholars.At present,the general synthesis methods of organoboron compounds include transition metal-catalyzed hydroboration reaction and transition metal-free hydroboration reaction.Great progress has been made in the metal-mediated hydroboration of unsaturated hydrocarbons.Many transition metal catalysts,such as Cu,Co,Rh,Zr,Ni,Ir,Ru,Fe and Au,have been applied in this field and are important components of hydroboration.However,compared with the hydroboration reaction catalyzed by transition metals,the use of abundant,non-toxic and environmentally friendly main group metals on the earth is relatively underdeveloped.At present,the hydroboration reaction without transition metal catalysis is limited to some acids,bases and a few special synthetic catalysts,so it is necessary to develop non-transition metal catalysts.In this thesis,we have realized the 1,3-diborization reaction of conjugated alkynes and HBpin without transition metal catalysis（NaHBEt₃ as catalyst）.The reaction conditions are mild,no transition metal catalyst is needed,and the alkyne substrate can be converted into diborization products containing alkenyl boron and alkyl boron functional groups in one step,thus providing a simple and practical method for synthesizing organic boron compounds,especially diboron compounds.