AuI -Catalyzed Haloalkynylation of Alkenes
Pedro D García-Fernández1, Cristina Izquierdo1, Javier Iglesias-Sigüenza1
1Departamento de Química Orgánica (Universidad de Sevilla) and Centro, de Innovación en Química Avanzada (ORFEO-CINQA), C/ Prof. García González 1, 41012, Sevilla, Spain.
Abstract:
The formal insertion of alkenes into aromatic chloro- and bromoalkynes takes place under cationic gold catalysis. This haloalkynylation reaction can be performed with cyclic, gem-disubstituted and monosubstituted alkenes, using BINAP, triazolo[4,3-b]isoquinolin-3-ylidene ligands or SPhos, respectively. The products were isolated in moderate to excellent yields and with complete diastereo- and regioselectivity; the halogen atom bonding the more substituted carbon of the alkene. Preliminary experiments showed that the enantioselective haloalkynylation of cyclopentene can be performed with (S)-BINAP to afford the insertion products with moderate to good enantioselectivities.
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