Enantioselective synthesis of 3-substituted 1-azabicyclo 2.2.1heptanes

摘要

A process for preparing a substantially pure enantiomer of a compound formula (I) wherein X is O or S; and   R² represents hydrogen, -CF₃, -OR⁷, -SR⁷, -NR⁷R⁸, -CN, -COOR⁷, -CONR⁷R⁸, or a saturated or unsaturated, substituted or unsubstituted hydrocarbon group, wherein R⁷ and R⁸ are independently selected from hydrogen and C₁₋₂alkyl provided that -NR⁷R⁸ is other than NH₂;   which process comprises cyclisation of a compound of formula (10) or salt thereof:    wherein X and R² are as defined in formula (I); and R⁴ is a labile leaving group and optionally epimersing the endo-diastereomer so prepared to produce the corresponding exo-diastereomer.