Stereoselective synthesis of 2-alkylidene-3-iminoindoles by reaction of 1,1-dianions with oxalic acid bis(imidoyl) chlorides
Treatment of dilithiated nitriles and sulfones with oxalic acid bis(imidoyl) chlorides resulted in a new cyclization reaction which provided a variety of (3-imino-2, 3-dihydro-1H-indol-2-ylidene)acetonitriles and -sulfones in good yields. The reactions proceeded by condensation of the dianions with the first imidoyl chloride group of the bis(imidoyl) chloride, subsequent intramolecular attack of the ortho carbon of the arylimino group onto the second imidoyl chloride group, and final aromatization. Excellent stereoselectivities were observed in most cases.
Langer
P
Institut fur Organische Chemie der Georg-August-Universitat Gottingen, Tammannstrasse 2, 37077 Gottingen, Germany, and Institut fur Anorganische und Analytische Chemie der Universitat Jena, August-Bebel-Strasse 2, 07743 Jena, Germ.
Wuckelt
J
Doring
M
Gorls
H