Asymmetric Synthesis of the C15⁻C32 Fragment of Alotamide and Determination of the Relative Stereochemistry

• Published in: Marine drugs Vol. 16; no. 11; p. 414
• Main Authors: Shi, Hao-Yun, Xie, Yang, Hu, Pei, Guo, Zi-Qiong, Lu, Yi-Hong, Gao, Yu, Huang, Cheng-Gang
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 30.10.2018; MDPI
• Subjects: Alcohol; Aldehydes; alotamide; Aquatic Organisms - chemistry; Asymmetric synthesis; Asymmetry; Boron; Boron - chemistry; Calcium; Calcium influx; Cyanobacteria; Cyanobacteria - chemistry; Depsipeptides - chemistry; Diastereoisomers; Enantiomers; Magnetic Resonance Spectroscopy; Metabolites; Molecular Structure; NMR; Nuclear magnetic resonance; Oxidation; Polyketides - chemical synthesis; Polyketides - chemistry; relative structural determination; Stereochemistry; Stereoisomerism; Synthesis; alotamide; asymmetric synthesis; relative structural determination
• ISSN: 1660-3397; 1660-3397
• DOI: 10.3390/md16110414

Alotamide is a cyclic depsipetide isolated from a marine cyanobacterium and possesses a unique activation of calcium influx in murine cerebrocortical neurons (EC 4.18 µM). Due to its limited source, the three stereocenters (C19, C28, and C30) in its polyketide fragment remain undetermined. In this study, the first asymmetric synthesis of its polyketide fragment was achieved. Four relative possible diastereomers were constructed with a boron-mediated enantioselective aldol reaction and Julia⁻Kocienski olefination as the key steps. Comparison of C NMR spectra revealed the relative structure of fragment C15⁻C32 of alotamide.