Premium
Enantioselective Syntheses and Absolute Configurations of Viridiene and Aucantene, Two Constitutents of Algae Pheromone Bouquets
Author(s) -
Boland Wilhelm,
Niedermeyer Uwe,
Jaenicke Lothar,
Görisch Helmut
Publication year - 1985
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19850680731
Subject(s) - chemistry , enantioselective synthesis , enantiomer , esterase , stereochemistry , saponification , kinetic resolution , absolute configuration , organic chemistry , synthon , diol , catalysis , enzyme
Viridiene ((+)‐ 6 ; (+)‐(3 R ,4 S )‐3‐((1 Z )‐1,3‐butadienyl)‐4‐vinylcyclopentene) and aucantene ((+)‐ 18 ; (+)‐(4 R ,5 R )‐4‐((1 E )‐1‐propenyl)‐5‐vinylcyclohexene) are constituents of the pheromone bouquets of several brown algae species. Key synthons to the title compounds are optically active γ‐lactones with known or experimentally determined absolute configurations. Horse liver alcohol dehydrogenase, which catalyses the oxidation of meso ‐ and racemic non‐ meso diols to chiral lactones, and pig‐liver esterase, which catalyzes the saponification of meso ‐diesters to chiral half‐esters, were utilized for the asymmetric synthesis of such precursors. The racemic non‐ meso diol rac ‐ 1 is converted to the two stereoisomeric γ‐lactones (+)‐ 2 and (+)‐ 3 which are readily separated. meso ‐Diol 12 is oxidized to the chiral γ‐lactone (−)‐ 11 . Its enantiomer (+)‐ 11 is obtained by enantioselective saponification of the meso ‐diester 9 with pig‐liver esterase. Appropriately designed syntheses lead from these chiral intermediates to both enantiomers (+)‐ and (−)‐ 6 of viridiene and (+)‐ and (−)‐ 18 of aucantene. In addition, kinetically controlled reduction of the racemic aldehydes rac ‐ 5a and rac ‐ 15 with horse liver alcohol dehydrogenase offers a convenient alternative to the enantioselective preparation of the enantiomers of the two hydrocarbons 6 and 18 . Chromatography of 6 on triacetylated cellulose as a stationary chiral phase confirms the enantiospecificity of the synthetic routes designed.