A stereocontrolled route to both enantiomers of the necine base dihydroxyheliotridane via intramolecular 1,3-dipolar addition using the same chiral precursor

Abstract

Diastereofacial selectivity in an enantiospecific intramolecular 1,3-dipolar addition is controlled by adjusting the size of the tether between the dipole and the dipolarophile to give 2,3-disubstituted pyrrolidines enantiomeric with respect to the newly generated stereogenic 2,3-centres depending on the tether size; this leads to Stereocontrolled synthesis of both enantiomers of the necine base dihydroxyheliotridane from chiral O-benzylglycidol.