Sc(OTf) 3 catalyzed intramolecular single-electron transfer of 2-alkyl-1,4-benzoquinones: synthesis of 6-chromanols from donor-acceptor cyclopropanes.

A Sc(OTf) 3 catalyzed intramolecular cyclization reaction of 2-alkyl-1,4-benzoquinone derived from D-A cyclopropane was discovered. This reaction involves single-electron transfer, proton-transfer, an aromatization driven spin center shift, and radical coupling processes, and offers an efficient method for the synthesis of 6-chromanols from D-A cyclopropanes.