DTBB-catalysed lithiation of 6-chloro-1-hexene and related systems: synthetically useful temperature-dependent behaviour
作者:Miguel Yus、Rosa Ortiz、Fernando F Huerta
DOI:10.1016/s0040-4039(02)00415-x
日期:2002.4
The reaction of 6-chloro-1-hexene 1 with lithium powder and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 5% molar) in THF at −78°C gives the corresponding organolithium intermediate 2, which by reaction with different electrophiles [ButCHO, PhCHO, Et2CO, (CH2)5CO, PhCOMe] affords, after hydrolysis with water, the expected products 3. The same reaction performed at −30°C gives cyclopentyl
6-氯-1-己烯的反应1与锂粉末和4,4'-二-催化量叔在THF -butylbiphenyl(DTBB,5%摩尔)在-78℃下,得到相应的有机锂中间体2,通过与不同的亲电子[卜反应吨CHO,苯甲醛,等2 CO,(CH 2)5 CO,PhCOMe]得到,用水水解后,预期的产品3。在-30℃下进行的相同反应可能通过将开链中间体2环化而得到环状有机锂化合物4,从而得到环戊基衍生物5。对于三阶导数6,由于相应的叔有机锂中间体7的极大的不稳定性,在-30℃下仅环状化合物10可以被分离,该叔有机锂中间体7甚至在-78℃下也经历了质子提取。在-78℃或-30℃下从烯丙基2-氯-苯基醚11中仅分离出相应的环状化合物14。在所有情况下,都假定发生了比自由基更好的碳负离子环化。