Theoretical study of the reaction of alkynes with furan catalyzed by AuCl₃ and AuCl

Abstract

ABSTRACT:A general scheme for the endo-and exo-cyclization of furan reactivity with [l-Au III, ICl x ] with (x ϭ 3, 1 and l-acetylene and vinylidene) complexes is investigated using density functional theory (DFT) code. Two conceivable mechanisms via a [4 ϩ 2] Diels-Alder process or carbene complex are analyzed. According to the activation energy values of the gold (III and I) catalyst, the first mechanism, which implies the Diels-Alder reaction of Au III , is thermodynamically favored and gives more evidence of the intramolecular addition of the furan with the alkynes. The second mechanism, presumably assisted by the spontaneous formation of the exo-vinylidene complexes and intermediates of gold (III, I) by forming the carbene complex, is kinetically favored. Additionally, we compare our results with other structures with intramolecular additions that exhibit the quasi-similarity of gold analogue structures. Differences in activation energies are observed, according to the functional used. Finally, we probe the solvent effects, which decrease the energy barrier in the path.

Experimental and Computational Evidence for Gold Vinylidenes: Generation from Terminal Alkynes via a Bifurcation Pathway and Facile C–H Insertions

“…Several studies have invoked their intermediacy, 4 but later calculations suggested alternative pathways. 5 The only exception is the formation of gold β-halovinylidene intermediates via AuCl-promoted [1,2]-halo migration of terminally halogenated alkynes (i.e., haloalkynes), 4d which was later supported by DFT calculations. 6 For synthetic usefulness, terminal alkynes are ideal, simple starting materials to access metal vinylidenes.…”

Theoretical study of weak CC double bond coordination in a gold (I) catalyst precursor

“…Indeed, an increasing number of papers concerning the use of the pre-catalyst gold or platinum in the catalytic systems [5][6][7][8][9]. It is important to notice for many catalysis reactions, there exists no direct experimental proof for most of the intermediates shown in the mechanistic proposals.…”

“…Gold catalysis underwent an impressive development and became an important tool in organic synthesis and offers new region-selectivity possibilities [4][5][6][7][8]. Considerable works were focused on a gold precursor in fundamental and applied research [2].…”

Enantiomerically pure tetrahydroisoquinolines from the gold-catalysed isomerization of substrates derived from furans and amino acids

“…This synthesis is based on a sequence which included the condensation of a furfural derivative 1 and an amino acid derivative 2, the catalytic asymmetric hydrogenation of 3 and the goldcatalysed cycloisomerization to give the phenol 6 [17][18][19][20][21][22][23][24][25][26][27][28][29] as key steps.…”