reduction of one of their C≡C triple bonds. The alkenyl groups have a cis arrangement of H and Al or Ga atoms across the C=C double bonds, which reflects the kinetically favoured situation. The cis/trans isomerisation is probably prevented from yielding thermodynamically favoured trans isomers; this is a result of an intramolecular bonding interaction between the α-carbon atoms of the remaining ethynyl
使用等摩尔量的二(叔)二
乙炔(R1)2Ge(C≡C–R2)2(R1 =
C6H5、
CH3;R1–R1 =
C6H4– ;R2 = 、CMe3、nBu、 )的处理-丁基)铝或-
氢化镓,R2E–H (E = Al, Ga),得到混合的烯基-炔基
锗烷,(R1)2Ge(C≡C–R2)[CE(CMe3)2}=C(H) )–R2],通过还原其中一个 C≡C 三键。烯基在 C=C 双键上具有 H 和 Al 或 Ga 原子的顺式排列,这反映了动力学有利的情况。顺式/反式异构化可能会阻止产生热力学有利的反式异构体;这是剩余
乙炔基的α-碳原子与配位不饱和
金属原子之间分子内键合相互作用的结果。