Amination [Synthetic Reagents]

　The Gabriel reagent is widely used as a nucleophilic aminating agent since its reactivity is reliable and its handling is easy.¹⁾ A variety of aminating agents analogous to the Gabriel reagent have been reported.
The potassium salt of imide 1 reacts with alkyl halide to give imide 2. 2 is treated with base or acid to give either N-Boc-amine 3 or N-methoxycarbonylamine 4, respectively. Moreover, 1 also serves as an acid nucleophile in the Mitsunobu reaction to allow for the conversion of hydroxy groups to amino groups. Therefore, 1 is a useful reagent to give monoprotected amines.²⁾

　Fukuyama and co-workers have demonstrated various reactions using the N-substituted sulfonamide 5.³⁾ Smooth reactions of 5 occur with alkyl halides under basic conditions and alcohols under Mitsunobu conditions to provide o-nitrobenzenesulfonyl (o-Ns) amines 6. The various o-Ns amines (Alloc, Boc, Cbz) 6 obtained from these reactions can be selectively deprotected, under the appropriate conditions, to afford the monoprotected amines 7 and 8. Furthermore, 7 can be converted to the primary amine in high yields via a second deprotection. 8 can be converted to the secondary amine in high yields by repeating the alkylation and deprotection process.⁴⁾

　 On the other hand, acetoxime O-(2,4,6-trimethylphenyl)sulfonate 9 has been reported as a useful electrophilic aminating agent. 9 reacts with Grignard reagents in the presence of a catalytic amount of magnesium chloride to afford primary amines in good yields.⁵⁾