Zirconocene-Initiated Intramolecular Hydride Transfer in N-Iso­alkyl-Substituted Propargylamines

Abstract

The unusual transformation of N-isoalkyl-substituted propargylamines into alkenylamines under the action of Cp2ZrCl2 and organoaluminum compounds (Me3Al, EtAlCl2) has been observed. The proposed mechanism, involving the N-isoalkyl-substituted propargylamine undergoing zirconocene-initiated intramolecular hydride transfer was supported by B3LYP/6-31G(d)/LanL2DZ calculations.

TaCl5‐Catalyzed Amidation of Carboxylic Acids with Amines

“…It should also be mentioned that the amidation of hexanoic acid with diisopropylamine is followed by the formation of impurities in a total amount of 20 %, which appear to be products of partial cleavage of the nitrogen‐carbon bond of the isopropylamine group under the action of tantalum(V) chloride. Previously, we observed elimination of the isopropyl moiety of the nitrogen atom in the Cp 2 ZrCl 2 ‐catalyzed reaction of N ‐isopropyl‐ substituted propargylamines with Me 3 Al [66] . However, the amidation of hexanoic acid with piperidine proceeds with high selectivity to form of carboxamide in 90 % yield (entry 7, Table 2).…”

“…Previously, we observed elimination of the isopropyl moiety of the nitrogen atom in the Cp 2 ZrCl 2 -catalyzed reaction of N-isopropyl-substituted propargylamines with Me 3 Al. [66] However, the amidation of hexanoic acid with piperidine proceeds with high selectivity to form of carboxamide in 90 % yield (entry 7, Table 2).…”