Total syntheses of mitragynine, paynantheine and speciogynine via an enantioselective thiourea-catalysed Pictet–Spengler reaction†
Isabel P. Kerschgens,Elise Claveau,Martin J. Wanner,Steen Ingemann,Jan H. van Maarseveen,Henk Hiemstra
Chemical Communications Pub Date : 11/13/2012 00:00:00 , DOI:10.1039/C2CC37023A
Abstract

The pharmacologically interesting indole alkaloids (–)-mitragynine, (+)-paynantheine and (+)-speciogynine were synthesised in nine steps from 4-methoxytryptamine by a route featuring (i) an enantioselective thiourea-catalysed Pictet–Spengler reaction, providing the tetrahydro-β-carboline ring and (ii) a Pd-catalysed Tsuji–Trost allylic alkylation, closing the D-ring.

Graphical abstract: Total syntheses of mitragynine, paynantheine and speciogynine via an enantioselective thiourea-catalysed Pictet–Spengler reaction