Silver-catalyzed asymmetric synthesis of 2,3-dihydrobenzofurans: a new chiral synthesis of pterocarpans.
2,3-Dihydrobenzofurans can be diastereoselectively prepared by condensation of aromatic aldehydes with 2,3-dihydrobenzoxasilepines under the catalysis of Ag(I) complexes, and in the presence of a source of fluoride ion. The application of this strategy by using chiral catalysts leads to a new enantioselective total synthesis of natural cis-pterocarpans and their trans isomers. Through this method, the first enantioselective total synthesis of the antifungal agent (-)-pterocarpin was achieved. In addition, a new entry into the heteroaromatic system of 2,5-dihydrobenzoxepine is also presented.
Jiménez-González
Leticia
L
Departamento de Química Orgánica, Universidad de Almería, 04120 Almería, Spain.
García-Muñoz
Sergio
S
Alvarez-Corral
Miriam
M
Muñoz-Dorado
Manuel
M
Rodríguez-García
Ignacio
I
D001572:Benzofurans / Q000138:chemical synthesis*; D002384:Catalysis; D008956:Models, Chemical; D036343:Pterocarpans / Q000138:chemical synthesis*; D012834:Silver / Q000737:chemistry*; D013237:Stereoisomerism
D001572:Benzofurans; D036343:Pterocarpans; D012834:Silver; C043168:coumaran