Gold(i) operational in synergistic catalysis for the intermolecular α-addition reaction of aldehydes across allenamides.

The intermolecular reaction of allenamides with aldehydes is reported. The designed approach relies on gold(i) and organocatalysis for activating the allenamides and the aldehydes respectively. Conditions to achieve an enantioselective version of this intermolecular reaction are defined.

Intramolecular C-H activation through gold(I)-catalyzed reaction of iodoalkynes.

The cycloisomerization reaction of 1-(iodoethynyl)-2-(1-methoxyalkyl)arenes and related 2-alkyl-substituted derivatives gives the corresponding 3-iodo-1-substituted-1H-indene under the catalytic influence of IPrAuNTf2 [IPr=1,3-bis(2,6-diisopropyl)phenylimidazol-2-ylidene; NTf2=bis(trifluoromethanesulfonyl)imidate]. The reaction takes place in 1,2-dichloroethane at 80 °C, and the addition of ttbp (2,4,6-tri-tert-butylpyrimidine) is beneficial to accomplish this new transformation in high yield. The overall reaction implies initial assembly of an intermediate gold vinylidene upon alkyne activation by gold(I) and a 1,2-iodine-shift.

Gold(I)-catalyzed hydroarylation reaction of aryl (3-iodoprop-2-yn-1-yl) ethers: synthesis of 3-iodo-2H-chromene derivatives.

An efficient entry to the preparation of elusive 4-unsubstituted-3-iodo-2H-chromenes has been accomplished as result of a catalytic cyclization. Thus, upon exposition of [(3-iodoprop-2-yn-1-yl)oxy]arenes to IPrAuNTf2 (3 mol %), in 1,4-dioxane at 100 °C, the desired heterocyclic motif is readily assembled. This process nicely tolerates a variety of functional groups and, interestingly, it is compatible with the presence of strong electron-withdrawing groups attached to the arene.