Metelski P D, Adamian V A, Espenson J H
Ames Laboratory, Iowa State University, Ames, Iowa 50011, USA.
Inorg Chem. 2000 Jun 12;39(12):2434-9. doi: 10.1021/ic990653k.
Different pathways for benzylic bromide transformations were examined under conditions of cobalt-bromide catalysis in acetic acid. It has been shown that benzylic bromides participate in the catalytic cycle through their catalyzed and noncatalyzed oxidation, through their reaction with Co(III), and through cobalt(II)-catalyzed solvolysis. The rates of the direct reduction of Co(III) by several benzylic bromides were measured under an argon atmosphere; the reaction occurs by a mechanism involving two forms of Co(III). The same reaction under an oxygen atmosphere initiates the cobalt-bromide-catalyzed oxidation of benzyl bromide, thus leading to the regeneration of inorganic bromide and the fast reduction of Co(III). Solvolysis of benzylic bromides plays only a minor role in the regeneration of inorganic bromide in glacial acetic acid.
在溴化钴催化于乙酸中的条件下，研究了苄基溴转化的不同途径。结果表明，苄基溴通过其催化和非催化氧化、与Co(III)的反应以及钴(II)催化的溶剂解作用参与催化循环。在氩气气氛下测量了几种苄基溴直接还原Co(III)的速率；该反应通过涉及两种形式Co(III)的机制发生。在氧气气氛下的相同反应引发了溴化钴催化的苄基溴氧化，从而导致无机溴化物的再生以及Co(III)的快速还原。苄基溴的溶剂解在冰醋酸中无机溴化物的再生中仅起次要作用。
