Trost’s Palladium Catalysed Asymmetric Allylic Alkylation (Pd-AAA). Literature Meeting Charette’s group Miguel St-Onge October 9 th , 2007. Presentation. Trost and Palladium p - allyl complexes Stereochemistry of oxidative addition and nucleophilic attack Counter anion effects
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Presentation • Trost and Palladium • p-allyl complexes • Stereochemistry of oxidative addition and nucleophilic attack • Counter anion effects • Synvs anti complexes • Nucleophilic approach on allyl terminus • Ligands and cartoon model • Classes of enantiodiscrimination processes • Types of nucleophiles and their application to total synthesis • Exceptions to the model • AAA with other metals • Total synthesis of Tipranavir • Conclusion
Pr. Barry M. Trost • Born in 1941 in Philadelphia • Received B.A. From University of Pennsylvania (1962) • Received Ph.D. at MIT under H.O. House’s supervision (1965) • Professor of chemistry at University of Wisconsin (1969) • Vilas research professor of chemistry (1982) • Professor of chemistry at Standford University (1987) • Takami professor of humanities and sciences (1990) • 803 publications (2006) • 38 honors and awards • 14 Patents Barry Trost web page at www.stanford.edu/group/bmtrost
Palladium • Discovered in 1803 by William Hyde Wollaston • Isolated from (NH4)2PtCl6 • Name comes from Greek goddess of wisdom, Pallas or Palladion • Atomic number 46 • [Kr] 4d10 • Pd0 = 18e square planar complexes • Pd(II) = 14e square planar complexes
Trost’s Study Trost, B.M; Weber, L. J. Am. Chem. Soc.1975, 97, 1611-1612
Study conclusion • Conclusions: • Stereospecificity of allylic alkylation has potentially important consequences in the application of the method for the creation of stereochemistry in acyclic and macrocyclic systems. • - Alkylation occurs on the face of the -allyl unit opposite to that of the palladium and use of soft nucleophiles are required for successful alkylation
Stoichiometric vs Catalytic • Conclusions: • Oxidative addition of palladium proceed with inversion of configuration and addition on -allyl palladium proceed also with inversion of configuration. • Net retention of configuration also occurs in enantiomeric catalytic system
Nucleophile Approach • Nucleophile addition is considered as a SN2-like displacement • Attack must be anti to the Pd leaving group (180o) • High impact for ligand working model analysis
Allyl Terminus Less substituted terminus More substituted terminus Trost, B.M.; Machacek, M.R.; Aponik, A. Acc. Chem. Res.2006, 39, 747-760.
Cartoon Model Trost, B.M.; Toste, F.D. J. Am. Chem. Soc., 1999, 121, 4545-4554. Lloyd-Jones G.C. Et. Al. Pure Appl. Chem., 2004, 76, 589-601.
Classes of Enantiodiscriminating Processes Ionization of the leaving group • Class A- Desymmetrization of meso diester • Class B- Desymmetrization of prochiral leaving group on the same carbon • Class C- Unsymmetrical p-allyl Pd complexes (achiral) Addition of the nucleophile • Class D- Meso-like p-allyl Pd complex • Class E- Unsymmetrical p-allyl Pd complexes (chiral)
Class A- Desymmetrization of meso Diester Trost, B.M.; Dudash, J., Jr.; Dirat, O. Chem-Eur. J. 2002, I81, 259-268. Trost, B.M.; Patterson, D.E., J. Org. Chem., 1998, 63, 1339-1341.
Carbon Nucleophiles in Total Synthesis Sulfone Type: Nitro type: Trost, B. M.; Chupak, L. S.; Lubbers J. Am. Chem. Soc. 1998, 120, 1732-1740. Trost, B. M.; Surivet, J.-P. Angew. Chem., Int. Ed.2000, 39, 3122-3124.
Oxygen Nucleophiles in Total Synthesis Primary alcohols: Carboxylates: Trost, B. M.; Weiping, T.; Schulte, J. L. Org. Lett. 2000, 2, 4013-4015. Trost, B. M.; Kondo, Y. Tet. Let.1991, 32, 1613.
Oxygen Nucleophiles in Total Synthesis Phenols Trost, B. M.; Toste, F. D. J. Am. Chem. Soc.1998, 120, 9074-9075. Trost, B. M., Tang, W. J. Am. Chem. Soc., 2002, 124, 14542-14543.
Nitrogen Nucleophiles Amines • Mono versus bisalkylation of primary amines • Regioselectivity on Pd p-allyl system • Speed of nucleophile versus p-s-p equilibration Trost, B. M.; Krische, M. J.; Radinov, R.; Zanoni, G. J. Am. Chem. Soc. 1996, 118, 6297-6298. You, S. L.; Zhu, X. Z.; Luo, Y. M.; Hou, X. L.; Dai, L. X. J. Am. Chem. Soc. 2001, 123, 7471-7472.
Nitrogen Nucleophiles in Total Synthesis Azides Trost, B. M.; Pulley, S.R. J. Am. Chem. Soc 1995, 117, 10143-10144. Trost, B. M.; Cook, G. R. Tet. Lett., 1996, 37, 7485-7488.
Nitrogen Nucleophiles in Total Synthesis Sulfonamide Trost, B. M.,; Oslob, J. D.; J. Am. Chem. Soc. 1999, 121, 3057-3064. Mori, M.; Nakanishi, M.; Kajishima, D.; Sato, Y. Org. Lett.2001, 3, 1913-1916.
Nitrogen Nucleophiles in Total Synthesis Imides Trost, B. M.,; Patterson, D. E.; Chem. Eur. J.1999, 5, 3279 Buschmann, N.; Rueckert, A.; Blechert, S. J. Org. Chem.2002, 67, 4325-4329.
Nitrogen Nucleophiles in Total Synthesis Trost, B. M.; Shi, Z. J. Am. Chem. Soc. 1996, 118, 3037-3038. Trost, B. M.; Madsen, R.; Guile, S. D.; Tet. Lett., 1997, 38, 1707-1710.
Sulfur Nucleophiles Pd -AAA Trost, B. M.; Organ, M. G.; O’Doherty, G. A. J. Am. Chem. Soc.1995, 117, 9662-9670. Trost, B. M.; Crawley, M. L.; Lee, C. B. J. Am. Chem. Soc.2000, 122,6120-6121.
Exceptions Trost, B. M.; Toste, D. F. J. Am. Chem. Soc. 2000, 122, 11262-11263. Trost, B.M.; Machacek, M.R.; Aponick, A. Acc. Chem. Res.2006, 39, 747-760.
Molybdenum AAA Transition State Krska, S. W.; Hughes, D. L.; Reamer, R. A.; Mathre, D. J.; Sun, Y.; Trost, B. M. J. Am. Chem. Soc. 2002, 124 (43), 12656-12657.