C2-symmetric bisamidines: Chiral Brønsted bases catalysing the Diels-Alder reaction of anthrones
| Author(s) : | Göbel Michael W Bats Jan W Gerd Dürner Deniz Akalay, |
| Publisher : | N/A |
| Publication Date : | 2008 |
| ISSN : | N/A |
| Abstract : | C2-symmetric bisamidines 8 have been tested as chiral Brønsted bases in the Diels-Alder reaction of anthrones and N-substituted maleimides. High yields of cycloadducts and significant asymmetric inductions up to 76% ee are accessible. The proposed mechanism involves proton transfer between anthrone and bisamidine, association of the resulting ions and finally a cycloaddition step stereoselectively controlled by the chiral ion pair. , |