in a highly regioselective manner. Their subsequent reaction with sulfonylacetylene afforded pyridyltitanium compounds, which, upon reaction with electrophiles, gave substituted pyridines virtually as a single isomer. When optically active nitriles were used in this reaction, chiral pyridines were obtained without loss of the enantiopurity. Alternatively, the azatitanacyclopentadiene prepared from an
乙炔、腈和
钛试剂 Ti(Oi-Pr)(4)/2 i-PrMgCl 的偶联以高度区域选择性的方式生成了新的氮杂
钛烷
环戊二烯。它们随后与磺酰
乙炔反应得到
吡啶基
钛化合物,在与亲电子试剂反应时,得到取代的
吡啶,实际上是单一异构体。当在该反应中使用旋光腈时,可以在不损失对映体纯度的情况下获得手性
吡啶。或者,由不对称
乙炔制备的氮杂
钛烷
环戊二烯与醛或另一种腈反应,再次以区域选择性方式得到具有四个不同取代基的
呋喃或
吡咯。