Diastereoselective Aerial Oxidative Cyclization of Methylenebisnaphthols Catalyzed by N-Hydroxyimides in the Presence of Fe3+ and Co2+-Mn2+ Catalysts

Aerial oxidative cyclization of methylenebisnaphthols to their corresponding spirans has been carried out using catalytic amounts of N-hydroxyimides and FeCl3 center dot 6H(2)O or Co(OAc)(2)center dot 4H(2)O-Mn(OAc)(2)center dot 4H(2)O. In this article we focus on the use of FeCl3 center dot 6H(2)O as a highly green and sustainable catalyst.