The Application Of Zinc And Magnesium Reagents With Halo Ketones Or Esters

The application of Grignard reagents and the type of Grignard reagents in organic synthesis is still the hot topic in organic chemistry research. It benefits to further study of these reagents and develop some meaningful reactions in organic synthesis. The thesis consists of the following two sections:1. Zinc is a relatively inexpensive, non-toxic metal. The low activity of organozinc reagents, once considered a major impediment, has now become one of their greatest assets. The reaction of allylzinc bromide reagents withα-halo ketones has been attracted our attention, and carried out. The experiment showed that the epoxides were efficiently obtained in high yields without additive; the rearrangement products---aldehydes or ketones were smoothly achieved catalyzed by TsOH·H2O based on the formation of epoxides; the nucleophilic addition products homoallylic alcohols were conveniently gained catalyzed by Yb(OTf)3. Herein, the different products were thus obtained in one reaction, under mild experimental conditions, high yields and one-pot procedure. The possible mechanism of the above mentioned transformations was proposed and discussed in this section.2. Magnesium Grignard reagent is one of the active organometallic reagents. The excellent reaction selectivity was achieved: only epoxides were obtained in the reaction of allylmagnesium bromide reagents withα-halo ketones under the proper conditions, without further rearrangement or the nucleophilic addition reaction.