Total synthesis of lamellarin G trimethyl ether through enaminone cyclocondensation

Abstract

A synthesis of pyrrolo[2,1-a]isoquinolines based on intramolecular condensation of an enaminone intermediate obtained by C-acylation of N-alkylated 6,7-dimethoxy-1-methyl-3,4-dihydroisoquinolinium salt was developed. This methodology was further applied to the total synthesis...

Chromenone‐Fused Pyrrolizines and Pyrrolizine Analogues of Lamellarins: Expanding the Lamellarin Family

“…A pendent aryl substituent is invariably also present at C-1. In view of the pronounced anticancer activity of representative alkaloids such as lamellarin D (2), lamellarin N (3) and lamellarin X (4), and synthetic analogues such as dehydrolamellarin J (5), [2] much recent effort has gone into the synthesis of lamellarins and their analogues, [3] and new methodology has often been trialled in formal or total syntheses of the simple derivative lamellarin G trimethyl ether (6). [4] Attention has also been paid to the synthesis of unnatural lamellarin variants in the hopes of finding compounds with more potent pharmacological activity.…”

Recent advances in the synthesis of chromenone fused pyrrolo[2,1-a]isoquinoline derivatives

“…They also developed a mild and nearly quantitative method for deprotecting isopropyl-protected phenols at room temperature with green reagent methanesulfonic acid without the need for chromatographic purification of intermediates. To extend the application of enaminone building blocks, Opatz and researchers 75 by bromination, by Pd-catalyzed Suzuki coupling reaction.…”