Abstract
N α -Methoxycarbonyl-(S)-tryptophan methyl ester is cyclised with 85% phosphoric acid to give (2S,3aR,8aS)-1,2-bis(methoxycarbonyl)-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole which on reaction with toluene-p-sulphonyl chloride gives (2S,3aR,8aS)-1,2-bis(methoxycarbonyl)-8-(p-tolylsulphonyl)-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole. This compound undergoes deprotonation with lithium diisopropylamide to the corresponding enolate which is quenched with a variety of alkylating agents resulting in alkylation, with retention of configuration, at C-2 of the pyrroloindole system. Subsequent treatment with trifluoroacetic acid brings about cycloreversion affording essentially optically pure α-alkylated tryptophan derivatives. The process is also applied, in the R-series.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
