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Published on: December 1, 2023
Stereochemistry of spongosoritins: beyond optical rotation
Andrea N L Batista1, Fernando M Dos Santos1, Alessandra L Valverde1
1Department of Organic Chemistry, Chemistry Institute, Fluminense Federal University, Outeiro de Sao Joao Batista s/n, Niteroi RJ 24020-141, Brazil. alessandravalverde@id.uff.br.
Abstract:
Stereochemical determinations based solely on the comparison of optical rotation (OR) measured at a single wavelength may commonly result in misassignments. Herein, we use vibrational and electronic CD, NMR, OR, and DFT calculations, to confirm the absolute configuration (AC) of the cytotoxic marine polyketides spongosoritin A (1) and 9,10-dihydrospongosoritin A (2) as (-)-(6R,8R) and (-)-(6R,8S), respectively. The AC of natural 1 and 2 has so far relied upon comparisons of OR values only. Besides showing the dependence of OR on achiral structural features, such as E/Z double bond geometries, an IR spectral marker is provided to help distinguish the geometric isomers of related molecules.
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