Development of new selective alylation catalysis based on characteristic feature of water/organic solvent biphasic interface

本文研究了水/正己烷两相催化苯硫醇在具有TPPTS配体的水溶性钯配合物存在下的烯丙化反应。在该反应中，以易得的烯丙醇为烯丙化试剂，优先得到支链的烯丙基硫化物。有趣的是，反应溶液的搅拌速度越高(1500rpm)，生成的支化烯丙基硫化物越多。在一般的化学反应中，这样的机械搅拌控制是非常罕见的。目前的选择性控制被认为是由于高活性的η^1-烯丙基钯中间体在水/正己烷界面产生的优先反应，通过苯硫醇的S_N_2反应生成主要是支链的烯丙基硫化物。

The present research deals with water/hexane biphasic catalytic allylation of benzenethiol in the presence of water soluble palladium complex having TPPTS ligands. In this reaction, easily obtainable allylic alcohols were used as allylation reagents and branched allyllic sulfides were preferentially obtained. Interestingly, the more high stirring speed of the reaction solution(1500rpm), the more branched allylic sulfides formed. Such control by mechanistic stirring is very rare in chemical reactions in general. The present selectivity control is considered to be arisen from preferential reaction of highly activeη^1-allylpalladium intermediate which is considered to be produced in the interface of water/hexane layers, by S_N2' reaction of benzenethiol giving mainly branched allylic sulfides.