02283nas a2200193   4500008004100000022001400041245015800055210006900213260000800282300001400290490000700304520154900311100002101860700001601881700002101897700002101918700002201939856012801961       2020                        eng d  a0022-326300aDFT/NMR approach for the configuration assignment of groups of stereoisomers by the combination and comparison of experimental and predicted sets of data0 aDFTNMR approach for the configuration assignment of groups of st  cMAR  a3297-33060 v853 a<p>Quantum mechanical/nuclear magnetic resonance (NMR) approaches are widely used for the configuration assignment of organic compounds generally comparing one cluster of experimentally determined data (e.g., C-13 NMR chemical shifts) with those predicted for all possible theoretical stereoisomers. More than one set of experimental data, each related to a specific stereoisomer, may occur in some cases, and the accurate stereoassignments can be obtained by combining the experimental and computed data. We introduce here a straightforward methodology based on the simultaneous analysis, combination, and comparison of all sets of experimental/calculated C-13 chemical shifts for aiding the correct configuration assignment of groups of stereoisomers. The comparison of the differences between the calculated/experimental chemical shifts instead of the shifts themselves led to the advantage of avoiding errors arising from calibration procedures, reducing systematic errors, and highlighting the most diagnostic differences between calculated and experimental data. This methodology was applied on a tetrad of synthesized cladosporin stereoisomers (cladologs) and further corroborated on a tetrad of pochonicine stereoisomers, obtaining the correct correspondences between experimental and calculated sets of data. The new MAE(Delta Delta delta) parameter, useful for indicating the best fit between sets of experimental and calculated data, is here introduced for facilitating the stereochemical assignment of groups of stereoisomers.</p>
1 aLauro, Gianluigi1 aDas, Pronay1 aRiccio, Raffaele1 aReddy, Srinivasa1 aBifulco, Giuseppe  uhttps://library.ncl.res.in/content/dftnmr-approach-configuration-assignment-groups-stereoisomers-combination-and-comparison