Premium
Variable stereochemistry in highly branched isoprenoids from diatoms
Author(s) -
Belt Simon T.,
Allard W. Guy,
Johns Lesley,
König Wilfried A.,
Massé Guillaume,
Robert JeanMichel,
Rowland Steve
Publication year - 2001
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.1053
Subject(s) - degree of unsaturation , chemistry , stereocenter , stereochemistry , double bond , terpenoid , diatom , two dimensional nuclear magnetic resonance spectroscopy , nuclear magnetic resonance spectroscopy , absolute configuration , botany , chromatography , organic chemistry , enantioselective synthesis , biology , catalysis
C 25 highly branched isoprenoid (HBI) alkenes are ubiquitous lipids found in geochemical samples around the globe. The origins of these widespread geochemicals are believed to be restricted to a limited number of diatoms, including Haslea ostrearia (and related species), Rhizosolenia setigera, and Pleurosigma intermedium. The unsaturation of the HBI alkenes ranges from 2–6 in different species and cultures. The number of stereogenic centres is usually limited to two in the HBI alkenes due to double bond positions. The relative and/or absolute configurations for these have been determined for a range of HBI alkenes produced from different diatoms cultured under a number of growth conditions. These determinations have involved a combined spectroscopic and chromatographic analysis using NMR spectroscopy and chiral gas chromatography, respectively. HBIs isolated from Haslea spp. belong to a specific structural type which exhibit configurational diastereoisomerism, while those isolated from P. intermedium and R. setigera represent a different structural type and usually exist as mixtures of geometric isomers only. HBIs are reported from a new species of diatom whose stereochemical properties lie between those found for Haslea spp. and P. intermedium. Chirality 13:415–419, 2001. © 2001 Wiley‐Liss, Inc.