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O ‐Benzylation of Carboxylic Acids Using 2,4,6‐Tris(benzyloxy)‐1,3,5‐triazine (TriBOT) under Acidic or Thermal Conditions
Author(s) -
Yamada Kohei,
Yoshida Saki,
Fujita Hikaru,
Kitamura Masanori,
Kunishima Munetaka
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201501172
Subject(s) - chemistry , reagent , organic chemistry , tris , triazine , catalysis , carboxylic acid , reaction mechanism , medicinal chemistry , biochemistry
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 °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.