First total synthesis of ß-carboline alkaloid trigonostemine G and its derivatives.

ABSTRACT

The ß-carboline core is the base structure of several biologically active natural and unnatural compounds. Herein, we report the first total synthesis of trigonostemine G, which is a newly isolated natural ß-carboline alkaloid from the twigs of Trigonostemon filipes. Synthesis of two structurally close derivatives of trigonostemine G is also reported. Key step of the syntheses involves a nucleophilic addition of 5-{[tert-butyl(dimethyl) silyl]oxy}-1H-indole to 1-formyl-ß-carboline building blocks.