title: Accurate prediction of the optical rotation and NMR properties for highly flexible chiral natural products.
abstract: Despite advances in electronic structure theory the theoretical prediction of spectroscopic properties remains a computational challenge. This is especially true for natural products that exhibit very large conformational freedom and hence need to be sampled over many different accessible conformations. We report a strategy, which is able to predict NMR chemical shifts and more elusive properties like the optical rotation with great precision, through step-wise incremental increases of the conformational degrees of freedom. The application of this method is demonstrated for 3-epi-xestoaminol C, a chiral natural compound with a long, linear alkyl chain of 14 carbon atoms. Experimental NMR and [α]D values are reported to validate the results of the density functional theory calculations.
authors.affiliation: School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand.
authors.forename: Muhammad Ali
authors.initials: MA
authors.lastname: Hashmi
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Andreassend
authors.forename: Robert A
authors.initials: RA
authors.lastname: Keyzers
authors.forename: Matthias
authors.initials: M
authors.lastname: Lein