preparation-enantiopure-non-activated-aziridines-synthesis-biemamide

Preparation of Enantiopure Non-Activated Aziridines and Synthesis of Biemamide B, D, and <em>epiallo</em>-Isomuscarine

Nitrogen-containing heterocycle aziridines are synthetically very valuable for the preparation of azacyclic and acyclic molecules. However, it is very ...

Hankuk University of Foreign Studies

Alkylative ring-opening of bicyclic aziridinium ion generated from 4-hydroxybutylaziridine with organocopper reagent was achieved successfully to afford 2-alkylsubstituted piperidine in high or moderate yield. This method allowed carbon-carbon bond formation of "non-activated" aziridine via aziridinium ion ring-opening in regio- and stereo-selective manner for the first time. This newly developed reaction was applied for an efficient synthesis of alkaloid with the representative example of conine and epiquinamide.

Alkylative Ring-Opening of Bicyclic Aziridinium Ion and Its Application for Alkaloid Synthesis.

The first expedient asymmetric synthesis of both enantiomers of 5,6-dihydrouracil-type marine natural products biemamides B and D was achieved from chiral 1-(α-methylbenzyl)aziridine-2-carboxylate. The key steps involved in the synthetic route are regio- and stereoselective aziridine ring opening via azide followed by a base-induced cyclization reaction. After comparison of ECD and optical rotation data of both synthetic enantiomers, the absolute configuration of natural biemamides B and D at the C5 position has been assigned as (-)-(5), which is an enantiomer to the originally proposed structure (-)-(5).

Total Synthesis and Stereochemical Revision of Biemamides B and D.

Among the large number of structurally diverse alkaloids, 2,6-disubstituted piperidine and its analogs have often been targeted when exploiting new synthetic techniques perhaps because of their strong pharmacological properties. This review outlines synthetic strategies to build the 2,6-disubstituted piperidine structural motif with a focus on stereochemical control of two substituents at C2 and C6. The key reactions in this process are then classified on the basis of how the piperidine rings were built with specific examples of natural products that control the stereochemical outcomes and their transition states.

Article	Year
Alkylative Ring-Opening of Bicyclic Aziridinium Ion and Its Application for Alkaloid Synthesis. Frontiers in chemistry\| PubMed ID: 31316970	2019
Total Synthesis and Stereochemical Revision of Biemamides B and D. Organic letters\| PubMed ID: 31638824	2019
Stereoselective synthesis of 2,6-disubstituted piperidine alkaloids. Organic & biomolecular chemistry\| PubMed ID: 32478370	2020

Nikhil Srivastava

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