A Pd-catalyzed oxa-(4+4)-cycloaddition between 1-azadienes and (2-hydroxymethyl)allyl
carbonates is described. Aurone-derived azadienes furnished polycyclic 1,5-oxazocines
in good yields. Interestingly, linear azadienes have also been involved and yielded
monocyclic heterocycles with complete regioselectivity. DFT calculations were carried
out to gain insight on this observation.
Key words
cycloaddition - catalysis - heterocycles - medium-sized rings - oxazocines - azadienes