Asymmetric Total Synthesis of (+)-Minfiensine by an Asymmetric Cascade Cyclization Strategy

Abstract

The Strychnos alkaloid minfiensine and a series of akuammiline alkaloids, such as vincorine, aspidophylline A, and picrinine, possess a common core skeleton, a 4a,9a-heterocycle-fused tetrahydrocarbazole. Efficient construction of this core structure in a highly enantioselective manner would facilitate the total synthesis of these alkaloids. In this article, we briefly summarize the established strategies for obtaining this core structure, together with the corresponding total-synthesis routes, and we describe our own effort on the development of a new strategy, the asymmetric cascade dearomative cyclization, for the efficient total synthesis of (+)-minfiensine.

Progress on the Synthesis and Applications of Aminals: Scaffolds for Molecular Diversity

“…Therefore, the ultimate way to evaluate the influence of all these variables is applying this knowledge to the arduous field of total synthesis. We selected a few examples of natural product containing the aminal framework within their structures [131][132][133][134][135][136][137][138][139][140][141][142][143][144][145][146][147][148] (Scheme 31) considering the following aspects of their respective synthesis: a) pathway for aminal formation, b) synthetic step which the aminal was formed and, when applicable, c) conditions used thereafter. When analyzing the first two variables we can see that, contrasting with the myriad of synthetic methods available for the construction of simpler aminal systems, the synthesis of aminals in the field of total synthesis is much more limited.…”

“…framework within their structures, 73,[131][132][133][134][135][136][137][138][139][140][141][142][143][144][145][146][147][148] and consider the following aspects of their respective syntheses: (a) the pathway for aminal formation, (b) the synthetic step during which the aminal is formed, and, when applicable, (c) the conditions used thereafter (Figure 1). When analyzing the first two variables we can see that, contrasting with the myriad of synthetic methods available for the construction of simpler aminal systems, the synthesis of aminals in the field of total synthesis is much more limited.…”