The first total synthesis of lathyranoic acid A (1) was accomplished stereoselectively in a linear sequence of 20 steps and an overall yield of 1.4%. This modular synthesis featured a cyclic, stereocontrolled Cu-catalyzed intramolecular cyclopropanation to construct the cis-cyclopropane unit, a Grubbs metathesis to construct the gamma-substituted cyclopentenone moiety, and an anion-mediated conjugate addition.
The first total synthesis of lathyranoic acid A (1) was accomplished stereoselectively in a linear sequence of 20 steps and an overall yield of 1.4%. This modular synthesis featured a cyclic, stereocontrolled Cu-catalyzed intramolecular cyclopropanation to construct the cis-cyclopropane unit, a Grubbs metathesis to construct the gamma-substituted cyclopentenone moiety, and an anion-mediated conjugate addition.
Preparation of 2,4-Disubstituted Cyclopentenones by Enantioselective Iridium-Catalyzed Allylic Alkylation: Synthesis of 2′-Methylcarbovir and<i>TEI-9826</i>
作者:Pierre Dübon、Mathias Schelwies、Günter Helmchen
DOI:10.1002/chem.200800495
日期:2008.7.28
A broadly applicable synthesis of chiral 2- or 2,4-substituted cyclopent-2-enones has been developed by combining asymmetric iridium-catalyzedallylic alkylation reactions and ruthenium-catalyzed ring-closing metathesis. Enantiomeric excesses (ee values) in the range of 95-99 % ee have been achieved. This method offers a straightforward access to biologically active prostaglandins of the PGA type.