Mono-N-protected amino acid ligands stabilize dimeric palladium(ii ) complexes of importance to C–H functionalization
| Autor: | Djamaladdin G. Musaev, Jared C. Lewis, Brandon E. Haines, Alexander S. Filatov, Joseph J. Gair |
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| Rok vydání: | 2017 |
| Předmět: |
010405 organic chemistry
Chemistry Stereochemistry Hydrogen bond Halogenation chemistry.chemical_element Cooperativity General Chemistry 010402 general chemistry 01 natural sciences 0104 chemical sciences Dimethylbenzylamine Catalysis chemistry.chemical_compound Electrophile Reactivity (chemistry) Palladium |
| Zdroj: | Chemical Science. 8:5746-5756 |
| ISSN: | 2041-6539 2041-6520 |
| DOI: | 10.1039/c7sc01674c |
| Popis: | Mono-protected amino acid (MPAA) ligands are used in a number of Pd-catalyzed C–H functionalization reactions. MPAAs have been proposed to bind to Pd(II) via κ2-(N,O) coordination, but such binding has not yet been experimentally validated. Herein, we report the synthesis and detailed characterization of a series of MPAA complexes prepared via cyclopalladation of dimethylbenzylamine in the presence of MPAAs. The isolated complexes exist as μ-carboxylato (MPAA) bridged dimers and feature potential M–M cooperativity and secondary sphere hydrogen bonding. Selective MPAA coordination and relay of stereochemistry, previously suggested to uniquely result from κ2-(N,O) MPAA coordination, are both observed. The isolated MPAA complexes undergo C–C and C–X (X = Cl, Br, I) bond formation when treated with electrophiles used for catalytic C–H functionalization. Stoichiometric iodination of MPAA palladacycles was found to proceed via a dinuclear palladium species with one equivalent of iodine in the rate limiting transition structure, and the isolated complexes also served as viable precatalysts for catalytic C–H functionalization. Together, these results provide a number of insights into the reactivity of Pd-MPAA complexes relevant to C–H bond functionalization. |
| Databáze: | OpenAIRE |
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