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The Observation of the C–H···O sp 3 Hydrogen Bond in Trisialic Acid Lactone and Its Implications for Cooperative Lactonization
Author(s) -
Chen ChienSheng,
Yu YiPing,
Lin BoChao,
GervayHague Jacquelyn,
Fang JimMin,
Hsu ChaoPing,
Wu ShihHsiung
Publication year - 2009
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.200900148
Subject(s) - chemistry , hydrogen bond , lactone , ab initio , stereochemistry , hydrogen , ab initio quantum chemistry methods , bond energy , catalysis , computational chemistry , crystallography , molecule , organic chemistry
The C–H ··· O sp 3hydrogen bond in trisialic acid lactones has been examined by using long‐range COSY (LRCOSY) and ab initio calculations. From an analysis of the LRCOSY spectra, 3 J correlations of B H 9 ax / A H 8 and C H 9 ax / B H 8 confirmed the existence of hydrogen‐bond connections of x +1 C 9 – x +1 H 9 ax ··· x O 8 . The theoretical bond energy of the hydrogen bond was estimated to be 1.0 or 1.6 kcal/mol by using two models. The acid‐catalyzed cooperative lactonization of oligosialic acids can be understood in terms of the additional C–H ··· O sp 3stabilization in the lactone product. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)