General approach for the total synthesis of the sarpagine related indole alkaloids (+)-Na-methyl-16-epipericyclivine, (−)-alkaloid Q3 and (−)-panarine via the asymmetric Pictet-Spengler reaction

The stereospecific total synthesis of (+)-N_a-methyl-16-epipericyclivine (1) was completed from d-(+)-tryptophan methyl ester] in an overall yield of 42% (eight reaction vessels). The optical rotation {α]_D +22.8 (c 0.50, CHCl₃)} obtained on this material confirmed that the reported optical rotation {α]_D 0 (c 0.50, CHCl₃)} ] was biogenetically unreasonable. The first total synthesis of (−)-alkaloid Q₃ (5) and (−)-panarine (6), via the intermediate vellosimine (18), is also described.