%0 Journal Article
%T Presence or absence of a novel charge-transfer complex in the base-catalyzed hydrolysis of N-ethylbenzamide or ethyl benzoate
%A Shinichi Yamabe
%A Wei Guan
%A Shigeyoshi Sakaki
%J Beilstein Journal of Organic Chemistry
%D 2013
%I 
%R 10.3762/bjoc.9.22
%X Reaction paths of base-catalyzed hydrolyses of isoelectronic substrates, Ph每C(=O)每X每Et [X = O (ethyl benzoate) and X = NH (N-ethylbenzamide)], were traced by DFT calculations. To simulate bond interchanges accompanied by proton transfers, a cluster model of Ph每C(=O)每X每Et + OH (H2O)16 was employed. For X = O, three elementary processes and for X = NH four ones were obtained. The rate-determining step of X = O is the first TS (TS1, the OH  addition step), while that of X = NH is TS2. TS2 of X = NH leads to a novel Mulliken charge-transfer complex, Ph每(OH)(O=)C   N(H2)每Et. The superiority or inferiority between the direct nucleophilic process or the general base-catalyzed process for TS1 was examined with the model Ph每C(=O)每X每Et + OH (H2O)n, n = 3, 5, 8, 12, 16, 24 and 32. The latter process was calculated to be more favorable regardless of the number (n, except n = 3) of water molecules. The counter ion Na+ works unfavorably on the ester hydrolysis, particularly on TS1. A minimal model of TS1 was proposed and was found to be insensitive to n.
%K basic hydrolyses
%K DFT calculations
%K ethyl benzoate
%K N-ethylbenzamide
%K reactive intermediates
%K transition states
%U http://dx.doi.org/10.3762/bjoc.9.22