155795-48-5Relevant articles and documents
Lewis acid mediated asymmetric Diels-Alder reactions of chiral 2-phosphonoacrylates
Zhu, Jia-Liang,Chen, Po-Erh,Huang, Hue-Wen
, p. 23 - 36 (2013/02/23)
2-Phosphonoacrylates containing four chiral alcohol auxiliaries were efficiently prepared and evaluated in Lewis acid mediated Diels-Alder reactions. Under the activation of SnCl4, all reactions performed in CH 2Cl2 at -65 °C exclusively afforded the endo (endo-to-carboxylate) cycloadducts with dr's ranging from 50:50 to >99:1. The best facial selectivity was obtained from the substrate bearing a (-)-phenylmenthyl group, to give adducts as (dr >99:1) or almost as (dr = 99:1) single diastereomers. Detailed strategies for the structural elucidation of the cycloadducts as well as a rationalization of the observed stereoselectivity are described.
Total synthesis of (-)-chokol A by an asymmetric domino Michael addition-Dieckmann cyclization
Groth, Ulrich,Kesenheimer, Christian,Kreye, Paul
, p. 2223 - 2226 (2007/10/03)
A convergent and asymmetric total synthesis of (-)-chokol A was accomplished in six steps starting from the α,β-unsaturated ester (E)-9 in an overall yield of 27% with an enantiomeric excess of 95%. The key step of this synthesis is the asymmetric tandem conjugate addition-Dieckmann cyclization of the higher-order cuprate 8 derived from vinyl bromide 7 with the α,β-unsaturated ester (E)-9. Georg Thieme Verlag Stuttgart.
Radical cyclizations - Synthesis of γ-lycorane
Cossy, Janine,Tresnard, Ludovic,Pardo, Domingo Gomez
, p. 1925 - 1933 (2007/10/03)
(+)-γ-Lycorane has been synthesized in ten steps from piperonylic alcohol. Two radical reactions were used successively to build the D and B rings. A formal synthesis of (+)-γ-lycorane was achieved via an optically active unsaturated aldehyde intermediate