Regiospecific, enantiospecific total synthesis of the 12-alkoxy-substituted indole alkaloids, (+)-12-methoxy-Na-methylvellosimine, (+)-12-methoxyaffinisine, and (-)-fuchsiaefoline.
[reaction: see text] The enantiospecific synthesis of 7-methoxy-d-tryptophan was completed by combination of the Larock heteroannulation process with a Schöllkopf-based chiral auxiliary in good yield. This ester was then employed in the first total synthesis of (+)-12-methoxy-Na-methylvellosimine, (+)-12-methoxyaffinisine, and (-)-fuchsiaefoline in regiospecific, stereospecific fashion in excellent overall yield. The asymmetric Pictet-Spengler reaction and enolate-driven palladium-catalyzed cross coupling processes served as key steps.
Zhou
Hao
H
Department of Chemistry, University of Wisconsin-Milwaukee, 3210 N. Cramer Street, Milwaukee, Wisconsin 53211, USA.
Liao
Xuebin
X
Cook
James M
JM