Reactions of 2-Formyl-3-methoxypropionitrile Derivatives as Electrophilic Reagent

Abstract

The reaction of 2-formyl-3-methoxypropionitrile derivatives (I, II, III) with benzenes (VIa-h) in the presence of an acid catalyst gave cis isomers of 2-methoxymethylene-3-phenylpropionitriles (VIIa-h) via electrophilic substitution of allyl cation (IV). The aluminum chloride-catalyzed reaction of III with the benzenes afforded 2-methoxymethyl-3, 3-diphenylpropionitriles (XVa-c) via electrophilic substitution of oxocarbonium ion (V). The same reactions of carbomethoxy analogs of I, II, and III were carried out to provide trans isomers of methyl 2-methoxymethylene-3-phenylpropionates (XIa-e) and a small amount of the carbomethoxy analog (XVIc) of XVc. In these reactions indan-(VIIIa, XIIa, b), triphenylpropane-(IXa, XIIIc), and indene-(XIVa, b) derivatives were obtainable via successive intra- or intermolecular substitutions of benzenes at the 2-methoxymethylene groups of VII and XI. The compounds VII and XV were converted into 2-dimethoxymethyl-3-phenylpropionitriles (X) and 2-cyano-1, 1-diphenyl-1-propenes (XVII), respectively, by the treatment of sodium methoxide in methanol. Some heterocycles such as 3-cyano-2-methoxychroman (XIX), 3-cyano-2H-chromen (XXIII), and 3-cyanoquinoline (XXIV) were simply derived from I or III following the above methods.