ASYMMETRIC SYNTHESIS OF α-SUBSTITUTED 5-HYDROXYTRYPTOPHAN DERIVATIVES

Article abstract of DOI:10.3987/COM-92-6313

5-hydroxytryptophan was converted to pyrroloindole (3), which on deprotonation with LDA and subsequent reaction with alkyl halides gave the C-2 alkylated derivatives (6-9) cleanly with retention of configuration.Reversion to the 5-hydroxytryptophan skeleton was then achieved by stirring in trifluoroacetic acid and deprotection by treatment with sodium in liquid ammonia followed by saponification.