Anti-Markovnikov Hydroarylation of Unactivated Olefins Catalyzed by a Bis-tropolonato Iridium(III) Organometallic Complex Gaurav Bhalla, ‡ Jonas Oxgaard, † William A. Goddard, III, † and Roy A. Periana* ,‡ Donald P. and Katherine B. Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089-1661, and Materials and Process Simulation Center, Beckman Institute (139-74), Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 Received March 9, 2005 Recently, we reported the first catalytic, intermolecular, anti-Markovnikov hydroarylation of unactivated olefins by a homogeneous, bis-chelating, O-donor Ir(III) complex, (acac-O,O) 2 - Ir(R)(L), based on the simplest -diketonate acetylacetonate (acac-O,O). With the ultimate objective of designing more active catalysts for this potentially useful reaction on the basis of structure function studies, we synthesized the related O-donor, bis-tropolonato Ir(III) organometallic analogues. Herein, we report that the new O-donor complex, (trop-O,O) 2 - Ir(Ph)(Py), is an active catalyst for the anti-Markovnikov hydroarylation of unactivated olefins and that theoretical calculations are consistent with catalysis proceeding via arene CH activation and olefin insertion. To date, two homogeneous catalysts 1,2 have been reported that catalyze the intermolecular hydroaryla- tion of unactivated arenes with unactivated olefins, eq 1, via the CH activation reaction. Catalyzing the hy- droarylation of olefins via the CH activation reaction is potentially useful 3 because of the possibility for (A) eliminating the use of corrosive Lewis acids, (B) regio- as well as stereocontrol, and (C) compatibility with a wide range of functional groups and reaction solvents such as water. One reported system that catalyzes the hydroaryla- tion of olefins via CH activation and with anti-Mark- ovnikov regioselectivity is based on the homogeneous, O-donor, late transition metal complex (acac-O,O) 2 Ir- (Ph)(Py), 1 (where acac-O,O is the O-bound acetyl- acetonate ligand). 1 To our knowledge, no other O-donor, late transition metal complex has been reported for the CH activation reaction. Given the expected differences of O-donor compared to more typical N-, C-, and P-donor ligands, there is a basis to anticipate different and potentially advantageous properties for O-donor com- plexes. Consistent with this, we have observed that, in addition to hydroarylation catalysis, 1 is thermally stable to air and protic media and that CH activation with this complex is not severely inhibited by olefins or water. 1a,4 The key limitation of this initial O-donor catalyst system is an activation barrier of ∼37 kcal/mol, which leads to reaction temperatures of ∼200 °C. Given the broad potential utility of efficient catalysts for olefin hydroarylation, the wide availability of O- donor ligands, the unique stability and reactivity prop- erties of this example of an O-donor late transition metal catalyst, and the limited study of O-donor ligands with late transition metals for CH activation reactions, we have begun a systematic study of this class of homogeneous O-donor complexes. The focus has been on structure-function relationships based on variations in the metal center 5 as well as the O-donor ligands. A short-term, focused objective of these studies is to design additional as well as more active and selective hy- droarylation catalysts. A longer term, broader objective is to determine whether the large class of O-donor ligands could be utilized for the generation of stable, active, and selective homogeneous catalysts based on the late transition metals. To begin to address this, it is important to show that (A) the chemistry of 1 is not unique to the O-donor acac-O,O ligands and (B) modi- * To whom correspondence should be addressed. E-mail: rperiana@ usc.edu. Fax: 213-821-2656. Tel: 213-821-2035. ‡ University of Southern California. † California Institute of Technology. (1) (a) Periana, R. A.; Liu, X. Y.; Bhalla, G. Chem. Commun. 2002, 3000. (b) Matsumoto, T.; Periana, R. A.; Taube, D. J.; Yoshida, H. J. Mol. Catal. A-Chem. 2002, 180, 1. (c) Matsumoto, T.; Periana, R. A.; Taube, D. J.; Yoshida, H. J. Catal. 2002, 206, 272. (d) Matsumoto, T.; Taube, D. J.; Periana, R. 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