Enantioselective palladium-catalyzed allylic alkylation reactions in the synthesis of Aspidosperma and structurally related monoterpene indole alkaloids

Abstract

Covering: up to the end of 2017 Enantioselective Pd-catalyzed allylic alkylations of prochiral enolates represent a powerful tool for the construction of all-carbon quaternary stereocenters. This review describes the emergence of such reactions as strategic linchpins that enable efficient, stereocontrolled syntheses of Aspidosperma and related monoterpene indole alkaloids.

Direct Access to (±)‐10‐Desbromoarborescidine A from Tryptamine and Pentane‐1,5‐diol

“…Indoloquinolizidines and harmicines featuring a tetracyclic core structure constitute an important part of the attractive indole alkaloids family . Owing to their structural diversity, these compounds display broad biological activities including opioid agonistic, blood pressure lowering and antitumoral activities .…”

Recent Advances and Perspectives in the Synthesis and Applications of Tetrahydrocarbazol‐4‐ones†

“…[5c] In this regard, oxidative cyclization reaction catalyzed by palladium complex has gained significant attention and become one of the most powerful tools to construct the carbazolone framework. [ 2 ]…”

“…Tetrahydrocarbazol‐4‐one derivatives with a broad range of functional groups are widely used as intermediates in the synthesis of alkaloids, such as aspidospermidine, kopsihainanine A, and vincadifformine. [ 2,3 ] Consequently, a series of elegant methods have been developed for the construction of this framework (Scheme 1). For instance, Fischer indole synthesis using cyclohexane‐1,3‐dione and phenyl hydrazine as substrates, is one of the most conventional method employed in this area (Scheme 1a).…”

Palladium‐Catalyzed Decarboxylative Asymmetric Allylic Alkylation: Development, Mechanistic Understanding and Recent Advances

“…Switching to more electron‐withdrawing protecting groups saw a marked increase in ee with the substrates containing an N‐Boc group affording an 87% ee . The extension of Pd‐catalyzed allylic alkylation to new substrate classes such as lactams and molecules possessing an indole fragment has enabled the synthesis of several other Aspidosperma and structurally related monoterpene indole alkaloids with important biological properties, as summarized by Stoltz in a recent review …”