Hydrogen-Bonding Activation of Gold(I) Chloride Complexes: Enantioselective Synthesis of 3(2H)-Furanones by a
Pilar Elías-Rodríguez1, Manuel Benítez1, Javier Iglesias-Sigüenza1
1Facultad de Química, Departamento de Química Orgánica, Universidad de Sevilla and Centro de Innovación en Química Avanzada (ORFEO-CINQA), C/Prof. García González, 1, 41012 Sevilla, Spain.
Abstract:
Enantioselective synthesis of 3(2H)-furanones has been achieved using the intermolecular H-bonding activation of gold(I) chloride complexes. A DM-BINAP [(R)-(+)-2,2'-Bis[di(3,5-xylyl)phoshino]-1,1'-binaphthyl] digold(I) dichloride complex in combination with a sulfonyl squaramide (SO2Sq) has been identified as the optimal catalytic system. The process involves a 5-endo-dig oxa-cyclization followed by stereocontrolled addition of indoles. Interestingly, the soft L*Au-Cl activation by H-bonding allowed the recovery of both L*Au-Cl and the activator after chromatographic purification.
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