Microwave-Enhanced Synthesis of Phosphonoacetamides
作者:Nadia Gruber、María C. Mollo、Mariana Zani、Liliana R. Orelli
DOI:10.1080/00397911.2010.530377
日期:2012.3.1
An efficient microwave protocol is described for the Michaelis-Arbuzov synthesis of secondary and tertiary N-aryl (and alkyl) (diethylphosphono) acetamides 1, by reaction of chloro- and bromoacetamides with triethyl phosphite in the presence of catalytic amounts of sodium iodide. Remarkable acceleration of the reaction (minutes vs. several hours) over conventional heating was achieved, together with improved product yields and purity, when bromoacetamides were employed as the substrates. Chloroacetamides were comparatively less reactive, leading to satisfactory yields only when a high excess of the reagent was employed.
Horner-Wadsworth-Emmons olefination of nonstabilized phosphonates. A new synthetic approach to β,γ-unsaturated amides
Aminolysis of readily accessible β-diethoxyphosphonyl-γ-butyrolactones 5 and 22 provides a convenient entry to (E)-β,γ-unsaturated amides 8 and 24 respectively. The key step of the aminolysis involves elimination of diethoxyphosporic acid from the corresponding β-hydroxyalkylphosphonates 7 and 23. Stereochemistry of the amides 8 and 24 results from their consecutive base catalyzed isomerization.