Aminations with O-Diphenylphosphinylhydroxylamine A Critical Evaluation
2014
Sosnovsky, George | Purgstaller, Klaus
A critical evaluation is presented of the scope of amination reactions with O-diphenylphosphinylhydroxylamine (ODPH) as compared to those using hydroxylamine-O-sulfonic acid (HOSA). Aminations with ODPH of isopropyl, t-butyl and cyclohexyl carbanions derived from the corresponding Grignard reagents, gave the corresponding amines in 36, 34 and 50 percent yields, respectively. The amination with HOSA of the same carbanions under similar conditions was unsuccessful. The aminative quarternization of the tertiary nitrogen of pyridine and quinoline with ODPH proceeded with comparable yields to those obtained with HOSA. An improved one flask amination with ODPH of indole, skatole and carbazole was achieved in 52-62 percent yields. The amination under the same conditions using HOSA gave consistently lower yields. Several other amination reactions which have been reported for HOSA were unsuccessful using ODPH. The conclusion is reached that overall the ODPH reagent is much less versatile than HOSA. Nevertheless, in the aminations of NH groups of heterocyclic compounds ODPH appears to be superior to HOSA and is the reagent of choice, in particular, since the preparation of ODPH is much less harzardous than that of HOSA.
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