Triethylborane-Induced Bromine Atom-Transfer Radical Addition in Aqueous Media: Study of the Solvent Effect on Radical Addition Reactions
作者:Hideki Yorimitsu、Hiroshi Shinokubo、Seijiro Matsubara、Koichiro Oshima、Kiyoyuki Omoto、Hiroshi Fujimoto
DOI:10.1021/jo010652l
日期:2001.11.1
yield. The bromine atom-transfer radical addition in benzene was not satisfactory. The addition proceeded smoothly in polar solvents such as DMF and DMSO, protic solvents such as 2,2,2-trifluoroethanol and 1,1,1,3,3,3-hexafluoro-2-propanol, and aqueous media. Ab initio calculations were conducted to reveal the origin of the solvent effect of water in the addition reaction. The polar effect of solvents
在环境温度下,用三乙基硼烷在水中处理溴乙酸乙酯和1-辛烯的混合物,以良好的产率提供4-溴modecanoate乙酯。苯中溴原子转移自由基的添加不令人满意。加入过程在极性溶剂(例如DMF和DMSO),质子溶剂(例如2,2,2-三氟乙醇和1,1,1,3,3,3-六氟-2-丙醇)和水性介质中顺利进行。进行从头算计算以揭示加成反应中水的溶剂作用的起源。通过介电常数判断的溶剂对溴原子转移和自由基加成步骤中过渡态的极性影响是相当重要的。计算表明,极性溶剂往往会降低过渡态的相对能。