3-Oxo-3-thia-2-azabicyclo[2.2.1]hept-5-en-2-carboxylates: the first isolation and characterization

Methyl and benzyl 3-oxo-3-thia-2-azabicyclo[2.2.1]hept-5-en-2-carboxylate were isolated at rt and characterized for the first time. Both endo and exo-isomers were observed. Under suitable experimental conditions (stoichiometric amount of sodium acetate, −40 °C or sodium borohydride/methyl iodide) ring opening of these compounds gave the corresponding thiosulfonates or methyl sulfides, respectively.