The synthesis of roeharmine and (-)-1,2,3,4-tetrahydroroeharmine

Article abstract of DOI:10.1016/S0040-4039(00)73513-1

The total synthesis of roeharmine 1 as well as an enantiospecific synthesis of (-)-1,2,3,4-tetrahydroroeharmine 2 has been achieved via the Pictet-Spengler reaction as a key step. The optical rotation of synthetic (- )-2 was found to be higher than that reported for the natural product. A possible mechanism for the racemization of 2 upon exposure to acid has been proposed and serves as a warning to alkaloid chemists who isolate ring-A alkoxylated indole alkaloids under acidic conditions.