Asymmetric catalytic oxidative cleavage of polycyclic systems: the synthesis of atropisomeric diazonanes and diazecanes

Oxidative cleavage of internal double bonds in polycyclic systems can give access to compounds containing medium-to large-sized rings. In this example, the nine-and ten-membered ring containing compounds that resulted from the mCPBA-mediated (mCPBA = meta-chloroperoxybenzoic acid) oxidative cleavage reaction were shown to exhibit atropisomerism. The reaction of the polycyclic system with catalytic amounts of ruthenium tetra-oxide followed by diol cleavage achieved the same synthetic goal. Use of the Nishiyama-Beller ruthenium-based catalysts enabled the synthesis of optically-enriched samples, providing the first example of an atropselective oxidative cleavage reaction.