Titanacyclobutenes or Titanium Vinyl Carbene Complexes? Reactivity of Organotitanium Species Generated by the Reaction of γ-Chloroallyl Sulfides with a Titanocene(II) Reagent
作者:Tomohiro Shono、Rie Kurashige、Ryo Mukaiyama、Akira Tsubouchi、Takeshi Takeda
DOI:10.1002/chem.200601418
日期:2007.5.7
conjugated dienes and vinyl cyclopropanes as major products, thus suggesting the formation of vinyl carbene complexes as intermediates. On the contrary, the organotitanium species generated from acyclic beta,gamma-disubstituted gamma-chloroallyl sulfides revealed titanacyclobutene-like reactivity, and their reaction with 1,5-diphenylpentan-3-one produced homoallyl alcohols. These organotitanium species
研究了用钛茂(II)试剂[Cp(2)Ti P(OEt)(3)}(2)还原γ-氯烯丙基硫化物生成的有机钛物种的反应性。由α-单取代的γ-氯烯丙基硫化物形成的有机钛物质与1,5-二苯基戊-3--3-酮和苯乙烯反应生成共轭二烯和乙烯基环丙烷作为主要产物,因此表明形成了乙烯基卡宾配合物作为中间体。相反,由无环β,γ-二取代的γ-氯烯丙基硫化物生成的有机钛物种显示出钛环丁烯样的反应性,并且它们与1,5-二苯基戊烷-3-one的反应生成了均烯丙基醇。这些有机钛物质不与苯乙烯反应,但与二氯苯基膦反应得到磷环丁烯。在β-单取代,γ-单取代和α,γ-二取代的γ-氯烯丙基硫化物的情况下,有机钛物质与1,5-二苯基戊-3--3-酮和苯乙烯反应。前者反应产生均烯丙基醇,后者反应产生乙烯基环丙烷或未共轭的二烯。这些结果表明,钛环丁烯和/或钛乙烯基卡宾配合物是通过γ-氯烯丙基硫化物的还原钛化反应生成的,具体取决于它们的取代方式。