Configurational Analysis by Residual Dipolar Couplings: Critical Assessment of “Structural Noise” from Thermal Vibrations

Abstract

The certainty of configurational assignments of natural products based on anisotropic NMR parameters, such as residual dipolar couplings (RDCs), must be amended by estimates on structural noise emerging from thermal vibrations. We show that vibrational analysis significantly affects the error margins with which RDCs can be back‐calculated from molecular models, and the implications of thermal motions on the differentiability of diastereomers are derived.

Study and quantification of the enantiodiscrimination power of four polymeric chiral LLCs using NAD 2D-NMR

“…This is possible because ''wrong'' configurations can change during a molecular dynamics simulation in 4D space with a pseudo-force field restraining only observables from NMR data and distance ranges from the constitution. [54][55][56][57][58][59] In the course of the investigation it turned out that it is not necessary to compute the 2 H quadrupolar coupling constants, K D i , (see eqn (3)) for each site. Instead, three selected values depending on the type of carbon hybridization were used for the computations, namely…”

Model-Free Approach for the Configurational Analysis of Marine Natural Products

“…Here, the application of the fc-rDG/DDD method as implemented in ConArch + [ 36 , 37 , 38 ] will be demonstrated on five complex natural products ( Scheme 1 ). Compounds 1a to 1c are synthetic derivatives or congeners of palau’amine, which is probably the most prominent cyclic dimeric pyrrole-imidazole alkaloid (PIA).…”