Experimental and Theoretical Study of the Effectiveness and Stability of Gold(I) Catalysts Used in the Synthesis of Cyclic Acetals

  1. Cordón, J. 1
  2. López-De-Luzuriaga, J.M. 1
  3. Monge, M. 1
  1. 1 Universidad de La Rioja
    info

    Universidad de La Rioja

    Logroño, España

    ROR https://ror.org/0553yr311

Revista:
Organometallics

ISSN: 0276-7333

Ano de publicación: 2016

Volume: 35

Número: 5

Páxinas: 732-740

Tipo: Artigo

DOI: 10.1021/ACS.ORGANOMET.5B01015 SCOPUS: 2-s2.0-84969812998 WoS: WOS:000372210300016 GOOGLE SCHOLAR

Outras publicacións en: Organometallics

Resumo

Different [AuL](+) fragments (L = tertiary phosphines, ylides, or NHC carbene) have been tested under mild conditions as suitable catalysts for the transformation of terminal or internal alkynes into the corresponding cyclic acetals upon reaction with ethylene glycol. We have obtained a moderate to negligible activity when using tertiary phosphines or nonstabilized ylides as ligands. However, a very high catalytic activity is reached when the IPr N-heterocyclic carbene ligand is used. We have analyzed the key stages in this type of gold-catalyzed reaction, namely, (i) electronic activation (alkynophilicity); (ii) protodeauration; and (iii) decomposition of the gold catalyst. The first two stages have been analyzed through DFT computation of the minimum-energy reaction pathways employing different catalysts. An explanation of the catalysts' stability has been proposed through the analysis of in situ time-resolved nuclear magnetic resonance spectra of the catalysts.