Porous Organic Polymers As Heterogeneous Ligands For Oxidative Heck?Hydrosilylation Reaction And Construction Of Dihydropyrazoloisoquinolines From Sul Fonylhydrazones

This thesis mainly focused on two aspects.One is we designed and synthesized a series of porous organic polymers(POPs).By employing these materials as heterogeneous ligands,oxidative Heck reactions of electronically unbiased alkenes and hydrosilylation of alkynes have been explored.The other is indium(III)promoted halocyclizations of N-propargylic sulfonylhydrazones to synthesize 5,6-dihydropyrazolo[5,1-a]isoquinoline which is potential bioactive nitrogen-containing compounds.Four chapters are included.Chapter 1:The Heck-Mizoroki reaction provides a versatile strategy to convert vinylic C-H bonds into C-C bonds.However,olefins that lack directing groups or electronic biased groups gave a mixture of Heck isomers with low selectivity.Most precedents achieve regioselectivity by using substrates that have an intrinsic electronic bias.Electron-rich vinyl ethers and vinyl amides favor coupling adjacent to the heteroatom to give the branched products,while electron-poor olefins,such as acrylates and styrenes,favor coupling at the terminal position to give the linear products.The scope of these reactions is severely limited,however,by challenges in controlling the product regioselectivities.In this chapter,we designed and synthesized thiophene-alkyne-based conjugated microporous polymers.By employing these CMP materials as selective regulators,Oxidative Heck Reaction between arylboronic esters and electronically unbiased alkenes provide highly selective linear-products(Scheme1).These ligands were utilized as catalytic sites and integrated into the skeleton of conjugated microporous polymers.The CMP material with bifunctional ligand feature(C?C and thiophene)and porous structure could achieve excellent linear-selectivity.in oxidative Heck reaction.Chapter 2:Vinylsilanes are versatile synthetic building blocks owing to their stability,convenient operation,non-toxicity,and propensity to undergo a variety of transformations.To date,alkyne hydrosilylation 1s the most atom-economic and environmental-friendly approach toward such compounds.Although transition-metal catalyzed hydrosilylation of alkynes is well established for the preparation of vinylsilanes,a serious issue hampering the widespread use of this method is the difficulty in regiocontrol and stereocontrol.For example,the hydrosilylation of a terminal alkvne can generate three possible products,(E)-?-,(Z)-?-,and?-vinylsilanes.In addition,the side reactions from oligomerization,hydrogenation and the multi-addition of alkyne also complicate the catalytic system.In this chapter.we have developed a highly selective Cobalt/POL-PPh3 catalyzed hydrosilylation of alkynes with PhSiH3 to produce(E)-?-vinylsilanes(Scheme 2).The reusability of Co/POL-PPh3 as a stationary phase in flow system was examined for the hydrosilylation and recycled 20 times with little loss of activity and selectivity.Chapter 3:The hydrosilylation of an internal alkyne can also generate four possible products,anti-?-,anti-?-,syn-?-and syn-?-vinylsilanes.In the past decades,a series of noble metal(Rh?Pd?Ir?Ru?Th?Au)catalyzed hydrosilylation reactions have selectively formed(E)-?-vinylsilanes.Several groups reported that non-noble metals cobalt could catalyze the hydrosilylation.As for internal alkynes without directing groups,cobalt-catalyzed hydrosilylation reactions is not an effective method to highly selectively generate syn-adducts.In this chapter,we have developed a highly regioselective Co(acac)2/POL-Xantphos@10PPh3 catalyzed hydrosilylation of unsymmetrical internal alkynes method for the synthesis of syn-?-vinylsilane products in heterocatalysis(Scheme 3).Furthermore,an excellent regioselective cobalt-catalyzed hydrosilylation of terminal alkynes with Ph2SiH2 to produce vinylsilanes has also been developed.This porous organic polymer could integrate the selectivity and activity merits of Xantphos ligands with the stability advantage derived from the high concentration of PPh3 ligands.The Co(acac)2/POL-Xantphos@10PPh3 recycled 7 times without loss of activity and selectivity.Chapter 4:Pyrazolo[l,5-a]pyridine framework have attracted increasing attention due to their promising biological activities.Typical examples of bioactive pyrazolo[1,5-a]pyridines include the well-known antiallergic and cerebroactive agent ibudilast,the novel adenosine A1 receptor antagonist FK838,the adenosine antagonist FK453 and a series of highly selective D4 receptors ligands.Although several strategies have been developed for the synthesis of 5,6-dihydropyrazolo[5,1-a]isoquinoline,they usually rely on the functionalization of-substrates with the preinstalled Pyrazole or 3,4-dihydroisoquinoline ring.As far as we know.methods that form both rings of the 5,6-dihyciropyrazolo[5,1-a]isoquinoline via a domino reaction have not been reported.In this chapter,we have developed a highly efficient indium(?)-promoted halocyclization method for the synthesis of 5,6-dthydropyrazolo[5,1-a]isoquinolines.And the product can be oxidized to afford pyrazolo[5,1-a]isoquinolines.In addition,hydrazones derived from cyclic ketones or olefin aldehydes gave the tetracyclic scaffold products followed by ring-expansion or electrophilic addition(Scheme 4).