AuI Iminophosphorane Complexes as Efficient Catalysts for the Cycloisomerization of Alkynyl Amides under Air, at Room Temperature, and in Aqueous or Eutectic-Mixture Solutions

María J Rodríguez-Álvarez; Cristian Vidal; Sören Schumacher; Javier Borge; Joaquín García-Álvarez

doi:10.1002/chem.201605303

Au^I Iminophosphorane Complexes as Efficient Catalysts for the Cycloisomerization of Alkynyl Amides under Air, at Room Temperature, and in Aqueous or Eutectic-Mixture Solutions

Chemistry. 2017 Mar 8;23(14):3425-3431. doi: 10.1002/chem.201605303. Epub 2017 Feb 7.

Authors

María J Rodríguez-Álvarez¹, Cristian Vidal¹, Sören Schumacher¹, Javier Borge², Joaquín García-Álvarez¹

Affiliations

¹ Laboratorio de Compuestos Organometálicos y Catalisis (Unidad Asociada al CSIC), Centro de Innovación en Química Avanzada (ORFEO-CINQA), Departamento de Química Orgánica e Inorgánica (IUQOEM), Facultad de Química, Universidad de Oviedo, 33071, Oviedo, Spain.
² Departamento de Química Física y Analítica, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Facultad de Química, Universidad de Oviedo, 33071, Oviedo, Spain.

PMID: 28052449
DOI: 10.1002/chem.201605303

Abstract

New iminophosphorane-phosphine Au^I complexes [AuCl(κ¹ -P-Ph₂ PCH₂ P{=NP(=S)(OR)₂ }Ph₂ )] (3 a,b) and [Au₂ Cl₂ (μ² -P,S-Ph₂ PCH₂ P{=NP(=S)(OR)₂ }Ph₂ )] (4 a,b) proved to be general, very efficient, and recyclable (up to four consecutive runs) catalysts for the cycloisomerization of alkynyl amides in water or choline chloride-based eutectic mixtures as green solvents. Remarkably, this cycloisomerization reaction took place under mild conditions (low catalyst loading, at room temperature, and in the absence of cocatalysts or protecting atmosphere) to give the corresponding alkylidene lactams by employing an efficient and sustainable methodology.

Keywords: cycloisomerization; deep eutectic solvents; gold; green chemistry; lactams.