A palladium-catalyzed facile and general method for the stereoselective synthesis of (E)-3-arylidene-3,4-dihydro-2H-1,4-benzoxazines and their naphthoxazine analogues

Palladium-catalyzed cyclocondensation of an aryl iodide with N-tosyl-2-(prop-2′-ynyloxy)aniline at room temperature is shown to constitute a convenient general method for the synthesis of (E)-3-arylidene-3,4-dihydro-2H-1,4-benzoxazines in moderate to very good yields. The method could also be extended to the synthesis of (E)-3-arylidene-2H-naphth1,2-b]1,4]oxazines. The regio- and stereo-selectivity of the process, short reaction time, operational simplicity, and use of inexpensive starting materials represent its attractive features.