Sequential Nucleophilic Addition/Intramolecular Cycloaddition to Chiral Nonracemic Cyclic Nitrones: A Highly Stereoselective Approach to Polyhydroxynortropane Alkaloids

Two new polyhydroxylated nortropane analogues closely related with Calystegines have been prepared in excellent chemical yields and complete selectivity. A synthetic strategy based on consecutive nucleophilic allylation, oxidation, and intramolecular dipolar cycloaddition was developed. The formation of key intermediate cycloadducts were observed to take place through the recently confirmed thermally induceded 2-aza-Cope rearrangement of nitrones.