An Efficient Synthesis of the Fully Elaborated Isoindolinone Unit of Muironolide A
作者:Qing Xiao、Kyle Young、Armen Zakarian
DOI:10.1021/ol401354a
日期:2013.7.5
An efficient stereocontrolled construction of the fully substituted isoindolone subunit of muironolide A is described. The approach is centered on the intramolecular Diels-Alder reaction between the enol form of the beta-keto amide and an alpha,beta,gamma,delta-unsaturated ester, followed by the installation of the cyclohexene double bond.
Bromation des enamines du prénal et du crotonaldéhyde. Voie d'accès aux ω-bromo aldéhydes et ω-bromo acétals correspondants.
Bromination of enamines of prenal and crotonaldehyde yields the corresponding omega-bromoaldehydes via the simple hydrolysis of iminium salts. The carbonyl function of these aldehydes can be protected as acetals or dioxolane. The overall process can be realized in a one pot procedure. The dioxolane is the starting material of a phosphonate which allows by condensation with beta-ionylidenacetaldehyde a direct access to the retinal with a 27.5% overall yield from the enamine 2