The 1,3- dipolar cycloaddition of unsaturated D- threo- hexaldonolactone 3 and a six- membered cyclic nitrone 11 led to a single adduct 15, which could be transformed into ( 1S, 2S, 3S, 9aS)- 2,3- dihydroxy- 1- hydroxymethyl- quinolizidine 28 related to epilupinine via a reaction sequence involving rearrangement of the six- membered lactone ring into a five- membered one, removal of the terminal carbon atom from the sugar chain, cleavage of the N- O bond, and the intramolecular alkylation of the nitrogen atom.
The 1,3- dipolar cycloaddition of unsaturated D- threo- hexaldonolactone 3 and a six- membered cyclic nitrone 11 led to a single adduct 15, which could be transformed into ( 1S, 2S, 3S, 9aS)- 2,3- dihydroxy- 1- hydroxymethyl- quinolizidine 28 related to epilupinine via a reaction sequence involving rearrangement of the six- membered lactone ring into a five- membered one, removal of the terminal carbon atom from the sugar chain, cleavage of the N- O bond, and the intramolecular alkylation of the nitrogen atom.