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