A concise synthesis of cyclobrassinin and its analogues via a thiyl radical aromatic substitution†
Abstract
A simple and concise approach for the synthesis of cyclobrassinin has been developed through a thiyl radical-mediated intramolecular aromatic substitution, with benzoyl peroxide as an efficient initiator and oxidant. The current method can also be utilized in the synthesis of 6 and 7-membered ring cyclobrassinin analogues in moderate to good yields. The transformation involves a formal radical 6 and 7-endo-trig cyclization of the corresponding dithiocarbamate derivatives, which were generated from indole-3-methanamines and tryptophan.