Enantioselective Photochemical Reactions of N-Phenyl Enaminones in Inclusion Complex Crystals Using a Chiral Host Compound.

Enantioselective reaction of N-methyl-N-phenyl-3-amino-2-cyclohexen-1-one derivatives to the corresponding N-methylhexahydro-4-carbazolones has been accomplished by photolysis in a water suspension of 1:1 inclusion compounds of the starting material with optically active host compounds derived from tartaric acid. 3-(N-Methylanilino)-2,5,5-trimethyl-2-cyclohexen-1-one formed two kinds of dimorphous crystals, and one of these gave an optically active carbazolone derivative by photolysis, but the other one was photochemically inert. X-ray structure analysis showed that two reaction centers, the phenyl and cyclohexenone groups of the reactant, are located in close and distant positions respectively in these two inclusion compounds.