O-Benzylation of Carboxylic Acids Using 2,4,6-Tris(benzyloxy)-1,3,5-triazine (TriBOT) under Acidic or Thermal Conditions
O-Benzylation of Carboxylic Acids Using 2,4,6-Tris(benzyloxy)-1,3,5-triazine (TriBOT) under Acidic or Thermal Conditions
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DOI：
10.1002/ejoc.201501172
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发表时间：
2015-12-01
影响因子：
2.8
通讯作者：
Kunishima, Munetaka
中科院分区：
文献类型：
--
作者：
Yamada, Kohei;Yoshida, Saki;Kunishima, Munetaka
本文报道了以2，4，6-三苄氧基-1，3，5-三嗪（TriBOT）为苄基化试剂，由羧酸合成苄酯的两种方法。反应在室温下在催化量的TfOH存在下（酸性条件）或在不存在TfOH的情况下在180-230 ℃下（热条件）进行。有趣的是，在两种条件下羟基羧酸的O-苄基化得到不同的产物：在酸性条件下的二苄基化产物和在热条件下的羟基酯。除此之外，其他证据表明，前一个反应通过S（N）1型机理进行，而后者通过S（N）2型机理进行。
Two methods for the synthesis of benzyl esters from carboxylic acids using the O-benzylating reagent 2,4,6-tris(benzyloxy)-1,3,5-triazine (TriBOT) have been developed. The reactions were conducted either in the presence of a catalytic amount of TfOH at room temperature (acidic conditions) or in the absence of TfOH at 180-230 degrees C (thermal conditions). Interestingly, the O-benzylation of hydroxy carboxylic acids under the two conditions afforded different products: The dibenzylated product under acidic conditions and the hydroxy ester under thermal conditions. In addition to these results, other evidence indicated that the former reaction proceeds through an S(N)1-type mechanism, and the latter by an S(N)2-type mechanism.