(4R)-3-Allenyl-4-(diphenylmethyl)oxazolidin-2-one, an unsubstituted allenamide.

The first X-ray structure of an unsubstituted allenamide, C(19)H(17)NO(2), is reported. The solid-state phase supports the notion that a key minimum conformation of allenamides can be invoked to rationalize the observed stereochemical outcomes in many of our methodological studies employing allenamides. This minimum conformation involves two important factors, i.

The first successful base-promoted isomerization of propargyl amides to chiral ynamides. Applications in ring-closing metathesis of ene-ynamides and tandem RCM of diene-ynamides.

[reaction: see text] A highly useful sequence of reactions is described here. These reactions consist of the first successful base-induced isomerizations of propargyl amides to chiral ynamides, applications of these novel ynamides in ring-closure metathesis leading to chiral 2-amidodienes useful for Diels-Alder cycloadditions, and the first successful tandem RCM of diene-ynamides.