Intramolecular reactions. Part VII. Cyclisation of aryl 3-chloropropyl sulphones
作者:R. Bird、C. J. M. Stirling
DOI:10.1039/j29680000111
日期:——
with potassium t-butoxide in t-butyl alcohol to give aryl cyclopropyl sulphones in high yields. The effects of substituents in the aromatic nucleus upon the rate of the reaction have been determined, and a rectilinear Hammett plot with ρ=+2·32 is obtained. Hydrogen atoms of the methylene group adjacent to the sulphonyl group are rapidly exchanged under basic conditions in deuteriated solvents, and
芳基3-氯丙基砜与叔丁醇钾在叔丁醇中反应,高收率得到芳基环丙基砜。确定了芳核中取代基对反应速率的影响,并获得了ρ = + 2·32的直线哈米特图。在碱性条件下,氘代溶剂中与磺酰基相邻的亚甲基氢原子快速交换,叔丁基[ 2 H]醇中的3-氯-1,1-二氘代丙基丙基对甲苯砜的环化速率为是叔丁基[ 1 H]醇中同位素正构砜的两倍。这些结果表明形成了中间碳负离子,并且ρ该反应获得的α-值是一种复合化合物,其在随后的闭环步骤中对碳负离子的平衡浓度及其亲核性具有相反的影响。结合当前关于环化的观点简要讨论了这一发现。