Mechanism of the Grignard Addition Reaction. XV. The Reaction of Grignard Reagents with Benzylpyridinium Chloride.

Abstract

The reaction of Grignard reagents with benzylpyridinium chloride produces 2-alkyl-N-benzyl-1,2- and 4-alkyl-N-benzyl-1,4-dihydropyridines. The mechanism seems to be polar, concerted except for the t-butylmagnesium reagent. The adducts may reduce the starting material to the unreported, non-alkylated N-benzyl-1,4-dihydropyridine. If the Grignard-alkyl is secondary, crystalline 4-alkylidene-1,4-dihydropyridines may be produced. Thermal rearrangements of N-benzyl-1,4-dihydropyridines lead to migration of the benzyl group