Lead tetraacetate mediated domino reactions on (R)-(−)-carvone-derived bicyclic unsaturated 1,2-diols and further rearrangements

Abstract Carvone derived octaline diols 1 and 2 were subjected to Pb(OAc) 4 -mediated glycol fission conditions. The isolable ‘half-cascade’ intermediate 3 was subjected to ozonolysis in methylene chloride, and subsequent basic treatment, providing bis-angularly substituted bicyclic lactone 5 via an intramolecular Cannizzaro type oxidoreduction. The ring expanded products 4 and 6 subjected to basic treatment afforded bicyclic aldols 8 and 7 , respectively, via a fused-to-bridged ring system interchange. The methods described here represent efficient approaches to a variety of conveniently functionalized chiral backbones offering chemoselectivity. The mechanistic pathways involved in both the oxidative cleavage induced domino transformations and in the base-induced ring-system interchange reactions are discussed.