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Updated: Mar 31, 2026

Preparation of Enantiopure Non-Activated Aziridines and Synthesis of Biemamide B, D, and epiallo-Isomuscarine
Published on: June 13, 2022
Efficient Synthesis and Stereochemical Revision of Coibamide A
Guiyang Yao1,2, Zhengyin Pan1, Chunlei Wu1
1Guangdong Key Laboratory of Nanomedicine, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen, Guangdong, 518055, P. R. China.
Abstract:
Coibamide A is a highly potent antiproliferative cyclodepsipeptide originally isolated from a Panamanian marine cyanobacterium. Herein we report an efficient solid-phase strategy for assembly of highly N-methylated cyclodepsipeptides, which is invaluable in generating coibamide A derivatives for structure-activity relationship studies. As a consequence of our synthetic studies, two stereochemical assignments of coibamide A were revised and the total synthesis of this natural compound was achieved for the first time.
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Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...

