Enantioenriched ω-bromocyanohydrin derivatives. Improved selectivity by combination of two chiral catalysts
2012 (English)In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 68, no 37, 7680-7684 p.Article in journal (Refereed) Published
Highly enantioenriched (R)-4-bromo-1-cyanobutyl acetate and (R)-5-bromo-1-cyanopentyl acetate were prepared by acetylcyanation of 4-bromobutanal and 5-bromopentanal, respectively, catalyzed by (S,S)-[(4,6-bis(t-butyl)salen)Ti(ÎŒ-O)] 2 and triethylamine followed by enzymatic hydrolysis of the minor enantiomer. A cyclic procedure employing the same two chiral catalysts provided inferior results due to a slowly reached steady state and, in reactions with the former substrate, to ring-closure of the free cyanohydrin formed as an intermediate in the reaction. Hydrolysis of the acylated cyanohydrins followed by AgClO 4-promoted cyclization provided (R)-2-cyanotetrahydrofuran and (R)-2-cyanotetrahydropyran in essentially enantiopure form.
Place, publisher, year, edition, pages
2012. Vol. 68, no 37, 7680-7684 p.
2-Cyanotetrahydrofuran, 2-Cyanotetrahydropyran, Acetylcyanation, Enzymatic hydrolysis, Kinetic resolution
IdentifiersURN: urn:nbn:se:kth:diva-101332DOI: 10.1016/j.tet.2012.05.090ISI: 000307802300024ScopusID: 2-s2.0-84864465486OAI: oai:DiVA.org:kth-101332DiVA: diva2:547820
FunderSwedish e‐Science Research Center
QC 201208292012-08-292012-08-272015-09-08Bibliographically approved