Teresa de Haro

Gold-Catalyzed Ethynylation of Arenes

A novel gold-catalyzed ethynylation of aromatic rings with electron-deficient alkynes via gold catalyzed C-H activation of both C(sp)-H and C(sp(2))-H bonds has been developed. This transformation provides aromatic propiolates difficult to prepare by other methods, highlighting the synthetic potential of gold chemistry.

Flexible Gold‐Catalyzed Regioselective Oxidative Difunctionalization of Unactivated Alkenes

Diols, diamines, and aminoalcohols are ubiquitous functionalities in complex organic molecules. From the seminal work of Sharpless and co-workers on the intermolecular osmiumcatalyzed asymmetric dihydroxylation and aminohydroxylation of alkenes, the development of alternative methods to access these privileged motifs has become a priority for synthetic organic chemists. In recent years, palladium catalysts in combination with PhI(OAc)2 as oxidant have been successfully used in the aminooxygenation and diamination of unactivated alkenes both intraand intermolecularly. These transformations rely on the oxidation of Pd to Pd species to facilitate the formation of C X bonds. 5] Coppercatalyzed and also metal-free reactions have been reported although the required acidic media in the later processes might limit its potential application in more elaborated settings [Eq. (1); TFA = trifluoroacetic acid]. Our research group has recently combined the unique carbophilicity of gold complexes with the Au/Au redox catalytic cycles to design new transformations. 9] Surprisingly, though, only one example of gold-catalyzed oxidative diamination of alkenes from ureas has been reported up to date. We envisioned that highly oxidized gold(III) intermediates generated in the presence of oxidants such as Selectfluor or PhI(OAc)2 could trigger the selective oxidative difunctionalization of alkenes [Eq. (2)].

Regio- and Enantioselective Aminofluorination of Alkenes†

Enantio- and regioselective: The intramolecular enantioselective aminofluorination of unactivated olefins was achieved by using a chiral iodo(III) difluoride salt. A highly regioselective aminofluorination of styrenes to access 2-fluoro-2-phenylethanamines was also developed.

Gold‐Catalyzed Stereocontrolled Synthesis of 2,3‐Bis(acetoxy)‐1,3‐dienes

Change the ligand, change the stereochemistry: 2,3-Bis(acetoxy)-1,3-dienes are obtained in a stereocontrolled manner by a novel tandem 1,2-/1,2-bis(acetoxy) rearrangement (see scheme, R(1) and R(2) are delta(+) stabilizing). Upon stabilization of the reaction intermediates, the ligand attached to gold controls the stereochemistry of the alkene in the second acetate migration, that is, N-heterocyclic carbenes (NHC) favor cis alkenes, whereas phosphine ligands selectively afford trans olefins.

Gold-catalyzed 1,2-/1,2-bis-acetoxy migration of 1,4-bis-propargyl acetates: a mechanistic study.

The late transition metal catalyzed rearrangement of propargyl acetates offers an interesting platform for the development of synthetically useful transformations. We have recently shown that gold complexes can catalyze a highly selective tandem 1,2-/1,2-bis-acetoxy migration in 1,4-bis-propargyl acetates to form 2,3-bis-acetoxy-1,3-dienes. In this way, (1Z,3Z)- or (1Z,3E)- and (1E,3Z)-1,3-dienes could be obtained in a stereocontrolled manner depending on the electronic and steric features of the ancillary ligand bound to gold and the substituents at the propargylic positions. In this work, we report an experimental study on the scope of this transformation, plus a detailed theoretical examination of the reaction mechanism, which has revealed the key features responsible for the reaction stereoselectivity. Synthetic applications towards the one-pot synthesis of quinoxaline heterocycles and tandem Diels-Alder processes have also been devised.

Gold-catalyzed oxidative aminoesterification of unactivated alkenes

This paper describes an efficient aminoesterification of unactivated alkenes through Au(I)/Au(III) redox catalytic cycles using Selectfluor or hypervalent iodine(III) reagents.Graphical abstract

[1,3-Bis(2,6-diisopropylphenyl)imidazol-2-ylidene]chloridogold(I)

The molecule of the title compound, [AuCl(C(27)H(36)N(2))], which belongs to a class of potentially catalytically active N-heterocyclic carbene complexes, has crystallographic C(2) symmetry and approximate C(2v) symmetry. The structure is isostructural with the Cu(I) and Ag(I) analogues. A previous report of the structure of the title compound as its toluene solvate [Fructos et al. (2005). Angew. Chem. Int. Ed. 44, 5284-5288] has inaccurate geometry for the complex molecule as a consequence of probable incorrect refinement in the space group Cc, instead of C2/c [Marsh (2009). Acta Cryst. B65, 782-783]. The Au-C bond length of 1.998 (4)  Å in the title compound is more consistent with the mean distance of 1.979 (14) Å found in 52 other reported [AuCl(carbene)] complexes than with the shorter distance of 1.942 (3) Å given for the refinement in the space group Cc for the toluene solvate and the value of 1.939 Å obtained from the recalculation of that structure in C2/c.