C-S Bond Synthesis And Slective Control Methods

The development of green synthetic method is a hot research topic in organic chemistry.The employment of ionic liquid as green catalyst,using enzyme as efficient catalyst and organic reactions in solvent- and catalyst-free conditions are green synthetic routes.Recently the research of solvent -free reaction,enzymatic, ionic liquid system for the synthesis of bioactive compounds widened the application of green chemistry in organic synthesis.The exploration of green synthesis in new reactions and the cascade reactions attracted the research interest of chemists.In this thesis,we firstly reported the unprecedented CAL-B -catalyzed anti-Markovnikov-type addition for the construct of C-S bond.Under the catalysis of a promiscuous lipases,Lipase B acrylic resin from Candida antarctica,a number of thiols,including some benzyl mercaptan,n-butyl mercaptan and dodecylthiol,were successfully added to a series of vinyl esters in moderate to excellent yields to prepare a series ofβ-(alkylthio) ethanol esters.Some control experiments demonstrated that the anti-Markovnikov addition was catalyzed by the active sites of lipases.Based on the lipase mechanism and chemical addition mechanism,we proposed a feasible mechanism for the promiscuous lipases-catalyzed anti-Markovnikov addition and desighned some experiments to preliminarily prove it.The selective enzymatic synthesis of thiol and vinyl ester in non-aqueous media was developed.The influence of the structure of vinyl ester and thiol was also evaluated.The enzymatic reactivity decreases as the chain of the vinyl ester increased. The addition is efficiently catalyzed by commercially available CAL-B at 50℃, affording the anti-Markovnikov and Markovnikov adducts in good yields.Moreover, the regioselectivity of the reaction can be controlled by the choose of organic media so that both the anti-Markovnikov(CAL-B + DMF) and the Markovnikov products (CAL-B + isopropylether) are now easily accessible in excellent selectivities. Thiolesters were furnished under the catalysis of D-amino acylase in DMF at 50℃. Regio- and chemicalselectivity in the reaction of thiols to vinyl esters is organic media and enzyme -dependent.Moreover,the influence factors of enzymatic synthesis such as enzyme sources,reaction media,reaction time,temperature were investigated.We have developed an efficient protocol for the anti-Markovnikov addition of thiols to vinyl ethers under solvent- and catalyst-free conditions.This new methodology constituted ease of reaction,short reaction time,high regioselectivity, high yields and green synthesis of thiol ester containing oxygen atom.The new reaction catalyzed by ionic liquid[bmim]OH to form the carbon -sulfur bond was explored.The influences of the structures of thiols,α,β-unsaturated carbonyl compounds and the reaction conditions on the Michael addition catalyzed by [bmim]OH were systematically investigated.The reaction was carried out at room temperature and could obtain good yields in 2-20 min.The ionic liquid could be recovered.A new strategy for the fast forming of carbon-nitrogen bond at room temperature was developed and the catalytic mechanism was studied.A new method for the cascade reaction was investigated.A basic ionic liquid [bmim]OH used as catalyst for the cascade reaction of Michael addition and acylation reaction in one pot was applied to synthesize a series of sulfur heterocycles beating both lactone and lactam functional groups.The influence of reaction conditions, substrate structure and acceptor structure on the cascade reaction were investigated.In this thesis,68 compounds were synthesized including 28 anti-Markovnikov adducts,6 Markovnikov adducts,4 acylates,24 Michael adducts,6 sulfur heterocycles.These compounds were characterized by ¹H NMR,¹³C NMR,FTIR and ESI-MS and 36 compounds have been confirmed to be new compounds.