Synthesis of allyldicyclopentadienyltitanium(III) complexes from dienes

摘要: Abstract Reaction of isopropylmagnesium bromide (2 moles) with a mixture dicyclopentadienyltitanium dichloride (1 mole) and suitable dienes in ether gives homologues π-allyldicyclopentadienyltitanium(III). For 1,3-dienes the yields allyldicyclopentadienyltitanium(III) complexes are order 70–80%; they lower for 1,4-dienes 1,5-dienes, while no obtained from allenes. The isolated axe most symmetrical ones possible isomers; absorption spectrum visible range can be used as guide identification isomers. substituents at carbon atoms 1 3 allyl group synposition. This explains why could olefins which diene system is part five- to eight-membered ring; however, cyclododecadienyl complex, ring closure syn-positions possible, was when 1,5,9-cyclododecatriene olefin. mechanism formation studied, first mole iso-C3H7MgBr reduces Cp2TiCl2 dicyclopentadienyltitanium(III) monobromide, converted unstable “active species” (Cp2Ti-iso-C3H7 or Cp2TiH) by second Grignard reagent. active species trapped give final π-allylic complex.