title: Enhanced diastereoselectivity in asymmetric crotylation reactions using propargylic dicobalt hexacarbonyl complexes.
abstract: [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.
authors.affiliation: Department of Chemistry, Metcalf Center for Science and Engineering, 590 Commonwealth Avenue, Boston University, Boston, MA 02215, USA.
authors.forename: M
authors.initials: M
authors.lastname: Sui
authors.forename: J S
authors.initials: JS
authors.lastname: Panek
mesh_terms: D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D007202:Indicators and Reagents; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D013237:Stereoisomerism
chemical_list: D007202:Indicators and Reagents; D009942:Organometallic Compounds; D003035:Cobalt