Kinetics and mechanisms of nucleophilic displacements with heterocycles as leaving groups. Part 10. Reactions of s-alkyl primary amines with pyryliums

Abstract

2,4,6-Triphenylpyrylium with s-alkylamines gives isolatable pyridiniums (which undergo S_N2 substitution with nucleophiles and elimination to olefins). 2,4,6-Triphenylpyrylium with 1-phenylethylamine and α-phenylbenzylamine forms the corresponding carbonium ions which may be trapped by nucleophiles. Isolated 1-cycloalkylbenzoquinoliniums (2) solvolyse but the S_N1 mechanism (for five-, six-, and seven-membered rings): for the cyclobutyl case an S_N2 reaction is also found.