From Noble Metal to Nobel Prize: Palladium-Catalyzed Coupling Reactions Giovanni Piersanti 26/10/2011 and 02/11/2011

From Noble Metal to Nobel Prize: Palladium-Catalyzed Coupling Reactions

Giovanni Piersanti

26/10/2011 and 02/11/2011

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Palladium?

Beautiful, but expensive jewellery metal (Noble Metals)

Car as part of the automotive catalysts(with Pt and Rh), where palladium is used to eliminate harmful emissions produced by internal combustion engines.

Electrodes (Pd/H2 as a reference)

Electronics for multi-layer ceramic capacitors (MLCC). These MLCC are used in electrical components for cellular telephones,personal and notebook computers, fax machines and in auto and home electronics.

Dental alloys.

Periodic Table

046_Palladium.htm

On the other hand, and not known to the general public, is the essential role of palladium catalysts in contemporary organic chemistry, a topic which has now been recognized withthe Nobel Prize for Chemistry 2010.

Nobel_prizes_chemistry_2010

http://www.periodicvideos.com/

http://www.periodicvideos.com/videos/046.htm

http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2010/

Palladium-based catalystsPalladium-catalyzed cross-coupling reactions

Creation of new C-C bonds



R. F. Heck, J. P. Nolley, J. Org. Chem. 1972, 37, 2320.

T. Mizoroki, K. Mori, A. Ozaki, Bull. Chem. Soc. Jpn. 1971, 44, 581.K. Sonogashira, Y. Tohda, N. Hagihara, Tetrahedron Lett. 1975, 16, 4467.

E. Negishi, A. O. King, N. Okukado, J. Org. Chem. 1977, 42, 1821.

Miyaura, Norio; Yamada, Kinji ; Suzuki, Akira Tetrahedron Letters 1979, 20, 3437Milstein, D.; Stille, J. K. J. Am. Chem. Soc. 1978, 100, 3636

Y. Hatanaka, T. Hiyama, J. Org. Chem. 1988, 53, 918;

a) D. S. Surry, S. L. Buchwald, Angew. Chem. Int. Ed. 2008, 47,6338; b) J. F. Hartwig, Acc. Chem. Res. 1998, 31, 852.

The Tsuji-Trost Reaction http://www.synarchive.com/reaction/96

Trost, B. M.; Fullerton, T. J. "New synthetic reactions. Allylic alkylation.” J. Am. Chem. Soc. 1973, 95, 292-294Trost, B. M.; Dietsch, T. J. "New synthetic reactions. Asymmetric induction in allylic alkylations." J. Am. Chem. Soc. 1973, 95, 8200-8201

This process is particularly useful for the coupling of two alkyl units, and the asymmetric veriant is commonly used in total synthesis.

Gaining popularity….. Buchwald-Hartwig Coupling http://www.synarchive.com/reaction/128

Cyanation of aryl halides







Where everything started from ?????

Angew. Chem. 1959, 71, 176. Wacker-Tsuji Oxidation

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Angew. Chem. Int. Ed. 2009, 48, 9034 – 9037: and butanale and acetic acid replace; acetone e butanone still active--- BOOM- C-C bond-forming process (Heck reaction), vynilacetate, allyl complex of palladium (pigreco-allyl comlplex).

Since then…….palladium-catalyzed cross-coupling reactions have come a long way, continuing popularity and success.

Tolerance of a wide range of functional groups on both coupling partners. Hence, it is possible to construct complex organic building blocks efficiently in fewer steps than by traditional stoichiometric reactions .

The development of ligands and co-catalysts allows for a fine-tuning of the reactivity. Hence, it is not surprising that these reactions are widely employed for various applications.

Easy transfer from gram-scale synthesis in academic laboratories toton-scale production in the pharmaceutical, agrochemical, and fine-chemical industries.

Hence, Nobel Prize being awarded for the three major coupling reactions:The Heck reaction, the Negishi coupling, and the Suzuki coupling reaction

a) K. C. Nicolaou, P. G. Bulger, D. Sarlah, Angew. Chem. Int. Ed. 2005, 44, 4442; b) C. Torborg, M. Beller, Adv. Synth. Catal. 2009, 351, 3027.

Heck ReactionIn the Heck reaction (probably better called as the Mizoroki–Heck reaction) (hetero)aryl, alkenyl, and benzyl halides are coupled with all kinds of alkenes in the presence of palladium catalysts to give the corresponding substituted alkenesIn general. ln the reaction proceeds with high stereo- and regioselectivity.







Syn addition, internal rotation, Syn elimination









Heck ReactionIn the Heck reaction (probably better called as the Mizoroki–Heck reaction) (hetero)aryl, alkenyl, and benzyl halides are coupled with all kinds of alkenes in the presence of palladium catalysts to give the corresponding substituted alkenesIn general. ln the reaction proceeds with high stereo- and regioselectivity.









Negishi CouplingEi-ichi Negishi and his group studied fundamental aspects of the coupling of various organometallic derivatives includingaluminum, magnesium, zinc, and zirconium compounds with aryl halides in the presence of palladium or nickel catalysts.However, the name Negishi coupling is nowadays associated with the nickel- and palladium-catalyzed crosscouplingreaction of organozinc compounds and organohalides.


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In addition to classical C(sp2) C(sp2) bond formation, the coupling of alkylzinc compounds allows for the formation of C(sp3)C(sp2) and C(sp3)C(sp3)

Suzuki CouplingOrganoboronic acids and boronates are able to transfer their organic moieties to the palladium center in base-assisted transmetalation reactions. Nowadays, the Suzuki reaction is probably the most important method for the

synthesis of all kinds of biaryl derivatives.

















These marvelous tools allow the artisans of this flagshipdiscipline of chemical synthesis to flourish and produce someof the most stunning masterpieces in the history of totalsynthesis.



Documents

From Noble Metal to Nobel Prize: Palladium-Catalyzed Coupling Reactions Giovanni Piersanti 26/10/2011 and 02/11/2011