The Synthesis Of Alkylboron Compounds And The Reactions Of Gem-Diborylalkanes

Organoboronic compounds are regarded as an important type of synthon in the field of organic synthesis.Many researchers apply them into different fields such as catalytic chemistry,material chemistry,medicinal chemistry and life science,because of their superior stability,hypotoxicity,proper reaction activity and good functional group tolerance.In the first chapter,we introduced and summarized the development history and current progress of the synthetic methods of unactivatied alkylboronic esters.Especially for the gem-diborylalkanes,the special structure makes them have huge potential applications in organic synthesis,and so we also summarized their synthetic methods and the present research progress in detail.In the past,the synthesis of different alkylboronic esters depends on the corresponding alkylhalides.For example,tertiary alkylboronic esters need tertiary alkylhalides be as the substrates.However,the condition for the preparation of tertiary alkylhalides is so harsh that many functional groups could not be compatible.In the second chapter,we described a copper catalyzed or promoted Suzuki-type reaction of primary alkyl electrophiles and gem-diborylalkanes.In this reaction,we can achieve the formation of saturated carbon-carbon bonds,and at the same time,we also can obtaine various alkylboronic esters including primary,secondary,tertiary alkylboron compounds.In addition,we provide a gram-scale synthetic method of gem-diborylalkanes.Allyl electrophiles are useful synthons in the organic synthesis for their high activity and different reaction sites.In the third chapter,we report a Cu/NHC catalyzed allylic substituted reaction of gem-diborylalkanes.In this reaction,we can obtain the branched y-selective products,and we also achieve the formation of quaternary carbon center.Moreover,when the chiral N-heterocyclic carbene(NHC)ligands are applied in the reaction,the asymmetric selective products can be yield.Multiborylated compounds are useful substrates for the construction of complex molecules.However,the lack of good synthetic methods for these compounds has been hindering their development.In the fourth chapter,we describe an efficient method for the synthesis of 1,1,2,2-tetra(boronates)and their derivatives.Furthermore,we also test the 1,1,2,2-tetra(boronates)in the reaction condition of the allylic substituted reaction in the second chapter,and it gives positive result.Transition-metal-catalyzed borylation of alkylhalides is an efficient method for the synthesis of alkylboronic esters.However the boylation of alkyl electrophiles by direct C-O bond cleavage have not been realized.In the last chapter,we reported a radical machanism is the most possible process for this reaction,which rarely appears in the C-O bond cleavage to our knowledge.A radical machanism is the most possible process for this reaction,which rarely appears in the C-O bond cleavage to our knowledge.Through the mechanism experiments,it suggests that this reaction is a heterogeneous catalytic process and the catalytic species are most likely to the in-situ reduced silver nanoparticles...