Using NMR to determine the relative stereochemistry of 7,7-diaryl-8,8′-dimethylbutan-1-ol lignans

•Syn- and anti-7,7-diaryl-8,8′-dimethylbutan-1-ol lignans were synthesized.•Analysis of NMR data for each isomers developed descriptors for each isomer.•Descriptors can be used to determine stereochemistry in undefined butanol lignans.

Due to their linear, freely rotatable, structure many natural 7,7-diaryl-8,8′-dimethylbutan-7′-ol lignans are reported without any stereochemical assignment. Analysis of synthetic 8,8′-dimethylbutanol lignans and analogues reveals significant differences between the NMR data of syn- and anti-isomers. This information was then used to determine the relative stereochemistry of the C-8 and C-8′ methyl groups in previously undefined natural products.

Graphical abstractDownload full-size image