Studies Of Selenium Grignard Reagent Synthesizing Organic Selenides

Organic Selenium compounds have attracted considerable interest in biology andchemistry field because of their bioactivity and great roles in organic synthesis. Manyco-workers treat their new reagents, new reactions and new bioactivity compounds asresearch hotspot. Although quite a number of procedures for the synthesis ofunsymmetrical Organic selenides have already been published, most of them, usuallyrequire the handling of unstable reagents, strongly alkali or acidic reaction, andtwo-step procedures. We summarize predecessor experience and find an efficientprocedure involving a one-step operation under neutral conditions is in demand.Under Selenium Grignard Reagent reacting with halide hydrocarbon condition, we doa series of exploring, our main conclusion were as following:1. Procedures of synthesizing carbon Grignard Reagent need free water and dry vesselunder nitrogen gas condition. When carbon Grignard Reagent reacts with seleniumpowder, the ratio of Se and halide hydrocarbon is 1:1, time is about 1 hour, keeping onslightly refluxing for completion under 45℃temperature. This procedure of Se by CGrignard Reagent: requiring magnesium of halide hydrocarbon, CuI is 15mo1% in thepresence of reactant, reaction time is controlled in 10 hours, magnesium is 3 timesdosage of selenium powder. Using this protocol is propitious to reduce theby-products, increase the crude product's purity and yield in synthesizing symmetryselenides. When stereo-hindrance effect and differently electronegative substituentexist, they give enormous effect to synthesize symmetry selenides.2. We utilize this protocol in synthesizing asymmetry selenides. Grignard Reagent ofmagnesium reacts with halide hydrocarbon, which and Se powder is prepared toSe-Mg Grignard Reagent. Under the condition of 3 time mol equivalent magnesium,CuI 15mo1%, 45℃temperature and 10 hours reaction time, this preparation is notefficient to facilitate unsymmetry selenides. We choose Bromobenzene and1-Bromo-4-methylbenzene under the condition of 1 time mol equivalent and variouscatalysts, via a series of spectrum datum analyzing, mainly produce a little thesymmetry phenyl selenide, but this protocol can not successfully produce asymmetry organic selenides. It proves our hypothesis rational, halide hydrocarbon GrignardReagent is propitious to unsymmetry organic selenides. Furthermore we searchdosage of magnesium and various catalysts to increase the yield of unsymmetryorganic selenides.