A concise total synthesis of phytotoxic radulanin A facilitated by the photochemical ring expansion of a 2,2-dimethylchromene in flow



The radulanins are biologically active bibenzyl natural products featuring a synthetically challenging 2,5-dihydro-1-benzoxepine core. In contrast with previous reports exhibiting lengthy strategies, we demonstrate the shortest synthesis of radulanin A to date, featuring a largely unexplored photochemical ring expansion reaction of a 2,2-dimethylchromene precursor. This work was adapted to a continuous flow setup for larger scale preparation, in view of biological investigations into the herbicidal properties of this natural product.

Version notes

The institution of E. Baudouin was corrected as "Sorbonne University". This institution was also added as a co-funder.


Supplementary material

Supporting information
Supporting tables and schemes Experimental procedures Copies of NMR spectra