Mild and efficient preparation of alkynepentacarbonyldicobalt complexes containing the chiral (R) -(+) -Glyphos ligand
摘要:
A range of diastereomeric alkynepentacarbonyldicobalt complexes containing the (R)-(+)-Glyphos ligand have been prepared in moderate to good yields under standard thermal conditions. Additionally, novel tertiary amine N-oxide mediated reactions have been developed which allow the synthesis of the same range of complexes at room temperature with good selectivity in consistently high yields. Optically pure (R)-(+)-Glyphos containing complexes have been obtained by preparative HPLC separation of the sets of diastereomeric compounds. Finally, the amine N-oxide techniques allow the rapid and clean preparation of alkynepentacarbonyltriphenylphosphinedicobalt complexes in good to high yields at room temperature.
Synthesis of Dicarbonyl(η<sup>4</sup>-tricarbonylcobaltacyclopentadiene)cobalt Complexes from Co<sub>2</sub>(CO)<sub>8</sub>. A General Route to Intermediates in Cobalt Carbonyl Mediated Alkyne Trimerization
作者:R. John Baxter、Graham R. Knox、Peter L. Pauson、Mark D. Spicer
DOI:10.1021/om980544y
日期:1999.1.1
cobaltacyclopentadiene complexes, derived from cobaltcarbonyl and two alkyne molecules and long believed to be intermediates in cyclotrimerization as well as in the formation of the (three-alkyne-derived) “flyover” complexes, can be isolated in selected cases if the mono(alkyne)−Co2(CO)6 complexes are treated at room temperature with just 1 equiv of alkyne in the presence of trimethylamine N-oxide. The complex (PhCCHCMeCMe)Co2(CO)5