As. Demir et al., Butenolide annelation using a manganese(III) oxidation. A synthesis of chromolaenin (Laevigatin), CAN J CHEM, 77(8), 1999, pp. 1336-1339
Citations number
32
Categorie Soggetti
Chemistry
Journal title
CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE
A procedure was developed for the annelation of a butenolide to an aromatic
ketone that highlighted a manganese(III) oxidation of an aromatic ketone.
The merit of this procedure was illustrated in a synthesis of Chromolaenin
(Laevigatin) (1) from 4,7-dimethyl-1-tetralone (2c). Oxidation of tetralone
and indanone with manganese(III) acetate in the presence of chloro- or bro
mopropionic acid or their Mn(II) salts furnished a alpha-haloesters 3a-d. A
n Arbuzov reaction of haloesters with triethylphosphite and an intramolecul
ar Horner-Watsworth-Emmons cyclization of the resulting phosphonate gave bu
tenolide 5a, b in 77-79% yield. This methodology was also applied to 4,7-di
methyl-1-tetralone (2c), and the corresponding butenolide 6 is synthesized
in 85% yield, which was then converted to Chromolaenin (1) using DIBAL-H.