Synthesis of optically pure .DELTA.4-tetrahydroquinolinic acids and hexahydroindolo[2,3-a]quinolizines from L-aspartic acid. Racemization on the route to vindoline
Synthesis of optically pure .DELTA.4-tetrahydroquinolinic acids and hexahydroindolo[2,3-a]quinolizines from L-aspartic acid. Racemization on the route to vindoline