Palladium pincer complexes with reduced bond angle strain: Efficient catalysts for the Heck reaction

Organometallics

Volumn 25, Issue 10, 2006, Pages 2409-2411

  Yoon, Myeong Sik ^a   Ryu, Dowook ^a   Kim, Jeongryul ^a   Ahn, Kyo Han ^a  

^a Pohang University of Science and Technology (POSTECH)   (South Korea)

Author keywords

[No Author keywords available]

Indexed keywords

BENZENE; BOND STRENGTH (CHEMICAL); CATALYSTS; CHEMICAL ANALYSIS; COMPLEXATION; ORGANOMETALLICS; REACTION KINETICS;

BOND ANGLE STRAIN; METALLACYCLES; PALLADIUM PINCER COMPLEXES;

PALLADIUM COMPOUNDS;

EID: 33744503976     PISSN: 02767333     EISSN: None     Source Type: Journal    
DOI: 10.1021/om0601246     Document Type: Article

References (24)

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3. Ahn et al. Manuscript in preparation.
4. Very recently, Soro et al. reported the synthesis of pincer complex 2a (M = Pd; L = Cl) via a Hg(II) intermediate: Soro, B.; Stoccoro, S.; Minghetti. G.; Zucca. A.; Cinellu. M. A.; Gladiali. S.: Manassero, M.; Sansoni, M. Organometallics 2005, 24, 53-61.
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6. Molecular computations were performed using Spartan '04 Windows from Wavefunction, Inc.
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12. 2): Rl = 0.0476, wR2 = 0.1385. For details, see the Supporting Information.
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19. A similar level of TON was reported, but at higher temperature (in refluxing NMP, 140 °C); see: Takenaka. K.; Uozumi, Y. Adv. Synth. Catal. 2004, 346. 1693-1696.
20. A reviewer commented that the increased flexibility of our pincer complexes may facilitate the dissociation of one of the pyridine rings to generate a more coordinatively unsaturated and active catalyst system. Also, the O-atom linkers would make the phenyl ring a stronger σ-donor to the metal, which in turn might increase the potentially rate determining oxidative addition step. These explanations are based on the proposition that the Heck reaction by these pincer complexes follows the Pd(0)/Pd(II) mechanism.
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24. 2 followed by flash column chromatography on silica gel (12/1 hexane/diethyl ether).