Lewis Acid Mediated [2,3]-Sigmatropic Rearrangement of Allylic alpha-Amino Amides
2004 (English)In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 69, no 9, 3043-3049 p.Article in journal (Refereed) Published
Boron trifluoride and BBr3 mediated [2,3]-sigmatropic rearrangements of allylic alpha-amino amides have been developed affording secondary amines in good yields. (E)-Crotyl and (E)-cinnamyl alpha-amino amides 2b and 2c exhibit excellent syn-diastereoselectivity upon rearrangement with either Lewis acid. The allylic amine 2a forms upon treatment with BF3 or BBr3 a five-membered heterocylic complex in which a single halide anion has been displaced by the carbonyl oxygen atom. The structures of the Lewis acid-amine complexes were elucidated using NMR spectroscopy. A plausible reaction mechanism, based on DFT calculations, is presented. Thus, BF3- or BBr3-complexed allylic amines 2 are shown to preferentially proceed, after deprotonation, via an endo transition state.
Place, publisher, year, edition, pages
2004. Vol. 69, no 9, 3043-3049 p.
Complexation, Nuclear magnetic resonance spectroscopy, Oxygen, Probability density function, Reaction kinetics, Stereochemistry
IdentifiersURN: urn:nbn:se:kth:diva-6873DOI: 10.1021/jo035618gISI: 000221268200017ScopusID: 2-s2.0-2142659321OAI: oai:DiVA.org:kth-6873DiVA: diva2:11705
QC 201009212005-09-272005-09-272010-09-21Bibliographically approved