Influence of steric symmetry and electronic dissymmetry on the enantioselectivity in palladium-catalyzed allylic substitutions
2003 (English)In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 68, no 8, 3258-3270 p.Article in journal (Refereed) Published
Chiral P,N-ligands with pseudo-C2 and pseudo-Cs symmetry based on chiral pyrrolidine and phospholane rings or on dinaphthatodihydroazepino and dinaphthatodihydrophosphepino moieties were prepared and assessed in the palladium-catalyzed allylic substitutions of allylic acetates. Higher selectivity was achieved with pseudo-C2-symmetric ligands based on the binaphthyl skeleton than with the analogous C2-symmetric P,P- and N,N-analogues. Pseudo-C2-type ligands had properties superior to those of pseudo-meso-type ligands when 1,3-diphenyl-2-propenyl acetate was used as a substrate, whereas the reverse situation was found for 3-cyclohexenyl acetate. Chirally flexible ligands, prepared by substitution of one of the rigid binaphthyl skeletons for a flexible biphenyl system, were found to induce chirality to the same extent as a 1:1 mixture of the rigid ligands.
Place, publisher, year, edition, pages
2003. Vol. 68, no 8, 3258-3270 p.
Catalysis, Mixtures, Palladium, Substitution reactions
IdentifiersURN: urn:nbn:se:kth:diva-6327DOI: 10.1021/jo026889eISI: 000182280900035OAI: oai:DiVA.org:kth-6327DiVA: diva2:11011
QC 201009202006-11-102006-11-102010-09-20Bibliographically approved