The observation of the C-H⋯Osp3 Hydrogen bond in trisialic acid lactone and its implications for cooperative lactonization
Journal
European Journal of Organic Chemistry
Journal Issue
20
Pages
3351-3356
Date Issued
2009
Author(s)
Abstract
Abstract The C–H ··· O hydrogen 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 stabilization in the lactone product. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Type
journal article