The Study To Synthesize α,β-Unsaturated Esters Containing A Trifluoromethyl Group By Suzuki Cross-coupling

Abstract:This thesis comprises three parts:Part I The Suzuki Cross-coupling reactions of arylboronic acids with Z-ethyl-3-iodo-4,4,4-trifluoro-2-butenoate (004) was firstly investigated in detail. It was found that using PdCl2(PPh3)2 as a catalyst, K3PO4·3 H2O as a base, and toluene as a solvent, the reactions of arylboronic acids with the substrate (004) could be readily accomplished to give the stereospecific E-ethyl-3-aryl-4,4,4-trifluoro-2-butenoates in high yields.Part II The Suzuki Cross-coupling reactions of trans-alkenylboronic acids and trans-cyclopropylboronic acids with Z-ethyl-3-iodo-4,4,4-trifluoro-2-butenoate (004) were firstly studied. It was found that under the optimum conditions (see Part I), the reactions of trans-alkenylboronic acids and trans-cyclopropylboronic acids with the substrate (004) could easily conduct to afford the corresponding stereospecific cross-coupling products. The steric hindrance of trans-2-tetrabutylcyclopropylboronic acid was found to have a remarkable effect on the cross-coupling reaction. It was also found that at the room temperature and in the presence of the cheap catalyst Pd(OAc)2 the cross-coupling reactions of trans-alkenylboronic acids with the substrate (004) could undergo smoothly to get the corresponding stereospecific products in high yields. Thus the success of this reaction provide a novel and practical approach to construct all trans conjugated dienoates containing a trifluoromethyl group.Part III Attention to synthesize trifluoromethyl substituted retinoates by Suzuki Cross-coupling reaction was examined. But we faced the difficulties of the dehydration and hydroboration of the intermediate E-4-methyl-4-hydroxyl-5-ene-6-(2,6,6-trimethyl-1-cyclohexene)-1-hexyne. These two points should be studied in the successive research work.