The solution mixtures of (R)-BINOL, Ti(OiPr)4 and H2O in 1:0.5:10 proportion in CCl4, corresponding to the conditions employed for catalyzing the enantioselective oxidation of sulfides to sulfoxides, contain a single titanium BINOLate species. NMR, CD and MS characterization allowed us to identify this species as (BINOLate)6Ti4(l3-OH)4 with tetrahedric symmetry consistent with a known crystallographic structure. By varying sample preparation conditions, some aspects of the catalytic behavior could be rationalized. Using racemic BINOL, several heterochiral species were observed in accord with reported non-linear effects in catalysis.
|Autori interni:||PESCITELLI, GENNARO|
DI BARI, LORENZO
|Autori:||PESCITELLI G; DI BARI L; SALVADORI P|
|Titolo:||Effect of water on BINOL/Ti(OiPr)4 solution mixtures: The nature of a catalytic precursor of enantioselective sulfoxidation|
|Anno del prodotto:||2006|
|Digital Object Identifier (DOI):||10.1016/j.jorganchem.2005.12.032|
|Appare nelle tipologie:||1.1 Articolo in rivista|