Synthetic Methodologies Of Functionalized Alkenes, 1,3-dienes And Conjugated Enynes

This dissertation consists of three parts:Firstly:We prepared 1,1-difunctional group reagents (E)-α-stannyl-α,β-unsaturated esters by the hydrostannylation of alkynyl esters with tributyltin hydride according to a literature method. We carried out the cross-coupling reaction of (E)-a-stannyl-α,β-unsaturated esters with acyl chlorides in the presence of Pd(PPh3)4/CuI to afford the corresponding (Z)-a-acyl-α,β-unsaturated esters.The next:We found that (E)-α-stannyl-α,β-unsaturated esters underwent an iododestannylation reaction to afford (E)-α-iodo-α,β-unsaturated esters, which reacted with (E)-alkenylzirconium(IV) complexes produced in situ by hydrozirconation of terminal alkynes in the presence of Pd(PPh3)4 to afford stereoselectively a variety of 1,3-dien-2-yl esters in good yields.We also investigated the Sonogashira coupling reaction of (E)-α-iodo-α,β-unsaturated esters with terminal alkynes in the presence of Pd(PPh3)4/CuI to afford the corresponding 1,3-enynyl esters in high yields.Finally:We found that terminal alkynes underwent clean cis-addition to acetylenic sulfones in the presence of catalytic palladium(Ⅱ) acetate and tris(2,6-dimethoxyphenyl)phosphine to produce (E)-1-sufonyl-substitutedl,3-enynes. Hydrostannylation of (E)-1-sulfonyl-substitutedl,3-enynes with tributyltin hydride in the presence of Pd(PPh3)4 afford 1,3-dienes containing tin and sulfone.