Carbomagnesiation Of Acetylenic Sulfones And Its Applications In The Synthesis Of Polysubstituted Alkenes

The stereoselective synthesis of polysubstituted alkenes remains one of the most interesting subjects in organic synthesis due to the fact that many biologically active compounds containing the structural unit of polysubstituted alkenes. In this dissertation, the Michael addition of Grignard reagents to acetylenic sulfones was studied and its further reaction with aldehydes was also investigated. This one-pot three-component reaction has the advantages of easily available materials, simple manipulation, mild reaction conditions. And it provides a new method for the stereoselective synthesis of polysubstituted alkenes, especially of tetrasubstituted alkenes. 1. We studied the carbomagnesiation of acetylenic sulfones with aryl Grignard reagent in the presence of catalytic CuCN. The hydrolysis of α-sulfonyl substituted vinyl magnesium reagents afforded trisubstituted alkenes. The reaction of α-sulfonyl vinyl magnesium reagents with aldehydes afforded tetrasubstituted alkenes containing the structural unit of allyl alcohols. The structure of the product 1,3-diphenyl-3-(p-methyphenyl)-2-(p-tolylsulfonyl)-2-propen-1-ol was determined by X-ray diffraction analysis, which suggests that the addition of aryl Grignard reagents to acetylenic sulfones is in the anti-fashion. 2. We studied the three-component tandem reaction of acetylenic sulfones, n-butylmagnesium bromide and aldehydes in the presence of CuCN. Tetrasubstituted alkenes was obtained in the ratio of Z/E ≈1:1. 3. We studied the three-component tandem reaction of acetylenic sulfones, allylmagnesium bromide and aldehydes in the presence of CuCN. This reaction afforded tetrasubstituted alkenes containing 1, 4-diene and allylic alcohol structural units regio-and stereoselectively. The NOESY spectrum shows that the major addition of allylmagnesium bromide to acetylenic sulfone is in the syn-fashion. 4. Fluorescence properties of the new products were analyzed by fluorescence spectrophotometer. It was found that the products have good fluorescence properties. And it was also observed that the electronic effect of the substituted group has a great influence on the fluorescence intensity and wavelength.