South African Journal of Chemistry
versão On-line ISSN 1996-840X
versão impressa ISSN 0379-4350
ARVIDSSON, Per I. et al. Application of (S,S)-pentacycloundecane bis(4-phenyloxazoline) as a novel chiral ligand for catalysis of the asymmetric Diels-Alder reaction of cyclopentadiene with 3-acryloyl-2-oxazolidinone. S.Afr.j.chem. (Online) [online]. 2009, vol.62, pp.60-66. ISSN 1996-840X.
The synthesis of the novel C1 symmetric (S,S)-pentacycloundecane bis(4-phenyloxazoline) ligand 5 and its evaluation as a chiral Lewis acid catalyst in the benchmark asymmetric Diels-Alder reaction between 3-acryloyloxazolidin-2-one (6)and cyclopentadiene (7) is reported. From the various metal salts screened the anhydrous magnesium perchlorate complex emerged as the best catalyst. The endo-cycloadduct product 8 was afforded in 81% enantiomeric excess with an endo:exo ratio of 98:2. An extensive screening of various metal ions as complexing agents was performed and is also reported.
Palavras-chave : Pentacycloundecane; oxazolines; chiral catalysis; Diels-Alder reaction.