The use of nonactivated iminodienophiles in the stereoselective aza-Diels-Alder reaction
2004 (English)In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 15, no 3, 445-452 p.Article in journal (Refereed) Published
This paper describes the preparation of nitrogen-containing bicycles by the aza-Diels–Alderreaction ofnonactivatediminodienophiles and cyclopentadiene. Readily available starting materials such as (S)-(−)-lactate and l-amino acids were used for the preparation of chiral aldehydes with high enantiomeric excess. The improved oxidation procedure by Dess–Martin periodinane was employed for the synthesis of l-alanine derived phthalimide protected aldehyde 14, which was difficult to obtain in high enantiomeric excess by other methods. The influence of different Lewis acids on the stereoselectivity of the aza-Diels–Alderreactionwas also investigated: It was found that the use of a combination of BF3·Et2O and TFA in the cycloaddition leads to complete racemization of the imine prepared from 14 whereas the use of TiCl4 gives the cycloaddition products 17a and 17b with high enantioselectivity (90%).
Place, publisher, year, edition, pages
Elsevier , 2004. Vol. 15, no 3, 445-452 p.
IdentifiersURN: urn:nbn:se:uu:diva-7338DOI: 10.1016/j.tetasy.2003.12.011OAI: oai:DiVA.org:uu-7338DiVA: diva2:131115