钯催化下(Z)-3-碘-3-三氟甲基-1-芳基烯丙醇与末端炔 烃的偶联反应

在Pd(PPh~3)~4/CuI催化下和使用1mol的NEt~3作碱和THF作溶剂，(Z)-3-碘-3-三氟甲基-1-芳基烯丙醇(1)与末端炔烃(3)反应得到正常的偶联产物5。当以NEt~3作碱和溶剂，Pd(PPh~3)~4/CuI催化1与3的交叉偶联反应生成化合物4。4为正常偶联化合物5在NEt~3存在下双键发生重排反应的产物。

Palladium-catalyzed cross-coupling of (Z)-3-iodo-3-trifluoromethyl-1- aryl allylic alcohols with terminal alkynes

The direct reaction of two equivalents of lithium diisopropylamide (LDA) with 2-bromo-3,3,3-trifluoropropene gave lithium trifluoromethylacetylide, which was then trapped with aromatic aldehydes to produce trifluoromethyl propargyl alcohols(2) in high yields. Treatment of 2 with LiAlH~4 and followed by I~2 provided (Z)- 3-iodo-3-trifluoromethyl-1-aryl allylic alcohols(1). In the presence of 1 equivalent of triethylamine, Pd(PPh~3)~4/CuI catalyzed cross- coupling of 1 with terminal alkynes in THF at 50℃ afforded conjugated (E)-3-alkynyl-3-trifluoromethyl allylic alcohols 5. When triethylamine was used as both base and solvent, the Pd(PPh~3)~4/CuI catalyzed crosscoupling of 1 with terminal alkynes led to ketones 4 instead of the expected 5. Mechanistic studies revealed that 5 was easily rearranged to 4 in the presence of triethylamine.