Enhanced diastereoselectivity in asymmetric crotylation reactions using propargylic dicobalt hexacarbonyl complexes.
[reaction: see text] Hexacarbonyl dicobalt complexes of propargylic acetals undergo Lewis acid catalyzed crotylation reactions with enhanced levels of diastereoselectivity (dr 6 to >20:1, syn/anti) while efficiently producing stereochemically well-defined homoallylic ethers. These results are in contrast to uncomplexed propargylic acetals, which undergo the crotylation reactions with low selectivity (dr < 2:1, syn/anti). After removal of the cobalt complex, the reactions afford propargylic ethers in high yields.
Sui
M
M
Department of Chemistry, Metcalf Center for Science and Engineering, 590 Commonwealth Avenue, Boston University, Boston, MA 02215, USA.
Panek
J S
JS
D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D007202:Indicators and Reagents; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D013237:Stereoisomerism
D007202:Indicators and Reagents; D009942:Organometallic Compounds; D003035:Cobalt