Massachusetts Institute of Technology Organic Chemistry 5.512 Unit 6 Stereocontrolled Aldol Reactions  Overview of the Stereochemistry of the Aldol Reaction and Substrate Control  Reagent Control: Chiral Auxiliary Strategies  Reagent Control: Chiral Controller Strategies  Reagent Control: Chiral Lewis Acid Catalyzed Aldol Reactions OH R1 4 3 O 2 General Review on Recent Advances Z R2 "Current Progress in the Asymmetric Aldol Addition Reaction" Palomo, C.; Oiarbide, M.; Garcia, J. M. Chem. Soc. Rev. 2004, 33, 65 The Aldol Retron II. Chiral Auxiliary Strategies 2,3-Syn Aldols Photograph removed due to copyright reasons. O Evans Oxazolidinone Boron Enolates O H N Bu H O Gage, J. R.; Evans, D. A. Org. Synth. Coll. Vol. 8, 339 R Me Review "Asymmetric Aldol Reactions Using Boron Enolates" Cowden, C. J.; Paterson, I. Organic Reactions 1997, 51, 1 B O Bu  2,3-Anti Aldols (1) Evans Dones D. A. Evans et al. J. Am. Chem. Soc. 2002 124, 392 and Org. Lett. 2002, 4, 1127 Table removed due to copyright reasons. (2) Oppolzer Sultams H H N S O O L.A. O Me Photograph removed due to copyright reasons. R OSiR3 (3) Masamune Esters Photograph removed due to copyright reasons. Table removed due to copyright reasons. Review "Boron-Mediated Aldol Reaction of Carboxylic Esters" Abiko, A. Acc. Chem. Res. 2004, 37, 387 see also Org. Synth. Coll. Vol. 10, 55 and 343 III. Chiral Controller Strategies (1) Paterson Boron Enolates R Photograph removed due to copyright reasons. O B Ian Paterson Cambridge University (2) Enamine Aldol Reactions Reviews (1) "Proline-Catalyzed Asymmetric Reactions" List, B. Tetrahedron 2002, 58, 5573 (2) "Enamine Catalysis Is a Powerful Strategy for the Catalytic Generation and Use of Carbanion Equivalents" List, B. Acc. Chem. Res. 2004, 37, 548 (2) "Enamine-Based Organocatalysis with Proline and Diamines" Notz, W.; Tanaka, F.; Barbas, C. F. Acc. Chem. Res. 2004, 37, 580 Hajos-Parrish-Eder-Sauer-Wiechert Reaction O O MVK aq AcOH 70° 1-2 h O O 1) 7.5 mol% (S)-proline DMF 16° 2-3 d 2) H2SO4, DMF 95° 4 h O O O 70-76% 92-94% enantiomeric purity Hajos, Z. G.; Parrish, D. R. Org. Synth. Coll. Vol. 7, 363 Figures removed due to copyright reasons. R O H H N R O H O III. Chiral Lewis Acid Strategies (1) Carreira Chiral Ti Catalyst Carreira, E. M.; Singer, R. A.; Lee, W. J. Am. Chem. Soc. 1994 116, 8837 Figures and Tables removed due to copyright reasons. (2) Evans Copper BOX and PYBOX Catalysts D. A. Evans et al. J. Am. Chem. Soc. 1999 121, 669 Figures removed due to copyright reasons.

Stereocontrolled Aldol Reactions (II)

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