Methanol addition to dihapto-coordinated rhenium complexes of furan.
The complexes [TpRe(CO)(L)(4,5-eta(2)-furan)], present as diastereomeric mixtures (L = (t)BuNC (1A, 1B), PMe(3) (2A, 2B), pyridine (3A, 3B), or 1-methylimidazole (4A, 4B)), undergo acid-catalyzed methanol addition in CH(2)Cl(2) at -40 degrees C, resulting in the syntheses of dihapto-coordinated 2-methoxy-2,3-dihydrofuran complexes. In all cases, two diastereomers resulted, one in which the oxygen of the dihydrofuran is oriented toward the L ligand (5A, 6A, 7A, and 8A), and one in which the oxygen is oriented away from the L ligand (5B, 6B, 7B, and 8B). In all cases, the methoxy group adds stereoselectively, anti to the metal fragment. In addition, the (t)BuNC complex 1 yields a dihapto-coordinated vinyl ether (5C) that results from ring opening of the protonated furan ligand. In no case does the diastereomeric ratio of products correlate with that of the starting material.
Friedman
L A
LA
Department of Chemistry, University of Virginia, Charlottesville, VA 22901, USA.
Harman
W D
WD
D005663:Furans / Q000737:chemistry*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D000432:Methanol / Q000737:chemistry*; D009941:Organomercury Compounds / Q000737:chemistry*; D012211:Rhenium / Q000737:chemistry*; D013237:Stereoisomerism
D005663:Furans; D009941:Organomercury Compounds; D012211:Rhenium; D000432:Methanol