Synthesis And Application Of Thioalkenyl Zirconocene

Alkenyl zirconocene compound prepared by hydrozirconation of alkynes in high yield and selectivity, is of great significance with highly reactive carbon-metal bond,which can be selectively converted to synthesize large amount of categories of compounds. Therefore, the synthesis of alkynyl sulfide, hydrozirconation of alkynyl sulfide, reaction of thioalkenyl sulfide with different electrophiles were studied in detail in the following parts:Part one:The synthesis of the alkynyl sulfidesWe have developed a facile one-pot synthesis of alkyl alkynyl sulfides. Based on the acidity of the hydrogen atom in the terminal acetyne the lithium alkynyl thiolate was generated via the reaction of lithiation of the alkynyes followed by the oxidative addition of cheap and readily available sulfur. Then the SN2reaction occurred between the lithium alkynyl thiolate and various halides to afford the relative alkynyl sulfides in moderate to good yields. In this method, sulfur simple substance as the source of sulfur moiety in the molecule, which can avoid the preparation of some toxic, smelly sulfur-containing organic intermediates Therefore, this procedure has the advantages of convenience, safety, good yield and atomic economy, owing to the avoidance of the loss of alkylthio moiety. The products were verified by IR,1H NMR,13C NMR, MS and HRMS.Part two:The synthesis and application of the thioalkenyl zirconoceneThe hydrozirconation of the alkynyl sulfides can selectivily generate bifunctionalized reagents-E-thioalkenyl zirconocene compound in the CH2Cl2, which undergoes a syn-addition. Due to the activity of the carbon-zirconium bond, the thioalkenyl zirconocene can react with diverse electrophiles (D2O/DCl, NBS, NCS, NIS, acyle chloride) to provide alkenyl sulfide. Therefore the thioalkenyl zirconocene intermediate acts as an active species in the highly selective synthesis of the polysubstitated olefins. The products were verified by IR,1H NMR,13C NMR, MS and HRMS.Part three:the application of the β-halogenated alkenyl sulfide Cross-coupling of (3-bromo alkenyl sulfide with Grignard could be carried out catalyzed by NiCl2(dppp)2, which provide a new method for the stereoselective synthesis of multi-substituted alkenes.