Ti-mediated addition of diethylzinc to benzaldehyde. The effect of chiral additives
2001 (English)In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 12, no 5, 755-760 p.Article in journal (Refereed) Published
In the presence of a chiral tridentate bissulfonamide, the titanium-mediated addition of diethylzinc to benzaldehyde gave alkylated products ranging from the (R)-enantiomer, formed with an e.e. of 26%, to the (S)-enantiomer, formed in 72% e.e. The enantioselectivity was also affected by the presence of additional chiral mono- and bidentate ligands, with the reactions proceeding via complexes containing the chiral sulfonamide and the additive. The: addition of (1R,2R)-2,2-diphenyl-,12-ethanediamine and (1S,2S)-1.3-diphenyl-1,2-ethanediamine gave the (S)-product with e.e. of 49% and the (R)-product with 16% e.e., respectively, whereas without additives the (R)-product was obtained in 26% e.e, In the presence of (1R,2R)-1,2-diphenyl-1,2-ethanediamine only (i.e. without the chiral sulfonamide), the (S)-product formed with a 3% e.e.
Place, publisher, year, edition, pages
2001. Vol. 12, no 5, 755-760 p.
disulfonamide-ti(o-iso-pr)4-dialkyl zinc system, bis(sulfonamido) bis(amide) complexes, catalytic enantioselective addition, functionalized secondary alcohols, dialkylzinc reagents, aliphatic-aldehydes, tetradentate ligand, crystal-structures, exchange-reaction, disulfonamides
IdentifiersURN: urn:nbn:se:kth:diva-20607ISI: 000168596200012OAI: oai:DiVA.org:kth-20607DiVA: diva2:339303
QC 201005252010-08-102010-08-10Bibliographically approved