abstract
A family of threefold symmetry phosphite ligands, P(O-BIN-OR)(3) (BIN = 2,2'-binaphthyl; R = Me, Bn, CHPh2, 1-adamantyl), derived from enantiomerically pure (R)-BINOL, was developed. Cone angles within the range 240-270 degrees were calculated for the phosphite ligands, using the computational PM6 Hamiltonian. Their rhodium complexes formed in situ showed remarkable catalytic activity in the hydroformylation of hindered phenylpropenes, under relatively mild reaction conditions, with full chemoselectivity for aldehydes, high regioselectivity, however with low enantioselectivity. The ether substituents at the ligand affected considerably the catalytic activity on the hydroformylation of 1,1- and 1,2-disubstituted aryl olefins. The kinetics of the hydroformylation of trans-1-phenyl-1-propene, using tris[(R)-2'-benzyloxy-1,1'-binaphthyl-2-yl] phosphite as model ligand, was investigated. A first order dependence in the hydroformylation initial rate with respect to substrate and catalyst concentrations was found, as well as a positive order with respect to the partial pressure of H-2, and a slightly negative order with respect to phosphite concentration and CO partial pressure. (C) 2011 Elsevier B. V. All rights reserved.
keywords
ASYMMETRIC HYDROFORMYLATION; PHOSPHORUS LIGANDS; PHOSPHITE LIGANDS; BULKY PHOSPHITE; KINETICS; STYRENE; SYSTEM; REGIOSELECTIVITY; TRANSFORMATIONS; 1-HEXENE
subject category
Chemistry
authors
Carrilho, RMB; Neves, ACB; Lourenco, MAO; Abreu, AR; Rosado, MTS; Abreu, PE; Eusebio, MES; Kollar, L; Bayon, JC; Pereira, MM
our authors
Mirtha A. O. Lourenço
Researcheracknowledgements
Authors are thankful to FCT funding, QREN/FEDER (COMPETE-Programa Operacional Factores de Competitividade), PTDC/QUI-QUI/112913/2009 and the NMR laboratory of Coimbra Chemistry Centre. Rui M. B. Carrilho thanks FCT for PhD grant SFRH/BD/60499/2009 and A. C. B. Neves thanks PTDC/QUI-QUI/112913/2009 Research grant.