Regioselective hydrophenylation of olefins catalyzed by an Ir(III) complex

✍ Scribed by Takaya Matsumoto; Roy A Periana; Douglas J Taube; Hajime Yoshida

• Book ID: 104421702
• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 293 KB
• Volume: 180
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/s1381-1169(01)00390-9

✦ Synopsis

The novel, anti-Markovnikov, arylation of olefins with benzene to produce straight-chain alkylbenzenes with higher selectivity than branched alkylbenzenes is catalyzed by [Ir(-acac-O,O ,C 3 )(acac-O,O )(acac-C 3 )] 2 (acac = acetylacetonato), 1 [J. Am. Chem. Soc. 122 (2000) 7414]. The reaction of benzene with propylene gave n-propylbenzene and cumene in 61 and 39% selectivities, respectively. The reaction of benzene and styrene afforded 1,2-diphenylethane in 98% selectivity. Considering the anti-Markovnikov regioselectivity and lack of inhibition by water, we propose that the reaction does not proceed via a Friedel-Crafts, carbocation, mechanism. Complex 1, amongst the various transition metal complexes examined, is the most efficient for catalyzing the anti-Markovnikov olefin arylation. The crystal structure of complex 1 was solved and is consistent with a binuclear Ir(III) structure with three different types of coordinated acac ligands as reported by earlier solution IR and NMR analyses. [Ir(-acac-O,O ,C 3 )(acac-O,O )Cl] 2 , 2, was prepared by the reaction of complex 1 with benzoyl chloride, and the crystal structure was also reported.