Sarah Siska. C. A. Morales Models for Carbonyl Addition Chem 206 ■ Useful reviews http://www.courses.fasharvardedu/-chem206/ Mengel, A Reiser, O. Chem. Rev. 1999. 99, 1191-1223 Chemistry 206 Gung, B. W. Tetrahedron 1996, 52, 5263-5301 Advanced Organic Chemistry Reetz, M. T. Angew. Chem. Int. Ed. Engl. 1984, 23, 556-569 Lecture number 20 Morrison, J D; Mosher, H. S. Asymmetric Organic Reactions Prentice Hall Inc. 197 Wipf, P; Kim, Y.J. Am. Chem. Soc. 1994, 116, 11678-11688, ref. 1-5, 7 The Evolution of Models for Carbonyl Addition ■ A problem Construct a model for the addition process in eq 1 using the principles learned Ms O BF3. 0Et2 (1) 1.3-Anti Aldehydes 1& 2 contain 2 stereocenters, each of which may infiuence the course of the addition process. For 1, the reaction is Felkin selective for all Fischer Cornforth Anh/Eisenstein Tomoda enolsilanes; however, for 2, this is not the case. Explain. For the answer see Felkin Evans,JACS1996,118,4322.(pd) OPMB 1, 2-Asymmetric Induction Models 1,3-Asymmetric Induction Models Merged 1, 2-and 1, 3-Asymmetric Induction Felkin Me Unpredicted, highly selective carbonyl additions OTMS R=Me,tBu≥97:3 BF3. OEt2 a Reading Assignment for this Week Carey Sundberg: Part A; Chapter 8 OPMB Reactions of Carbonyl Compounds Monda Matthew d shair November 4.2002 R=t-Bu96:4 R=Me4:96http://www.courses.fas.harvard.edu/~chem206/ R OTMS H Rb O OP BF3•OEt2 Me H iPr O OPMB Me iPr OH OPMB R O Me H iPr O OPMB Me iPr OH OPMB R O R OTMS BF3•OEt2 Rb OH OP R O iPr OH OPMB R O Me Sarah Siska, C. A. Morales Chem 206 Matthew D. Shair Monday, November 4, 2002 ■ Reading Assignment for this Week: Carey & Sundberg: Part A; Chapter 8 Reactions of Carbonyl Compounds Models for Carbonyl Addition Chemistry 206 Advanced Organic Chemistry Lecture Number 20 The Evolution of Models for Carbonyl Addition ■ Useful Reviews (1) 1,3-Anti Construct a model for the addition process in eq 1 using the principles learned thus far in the course. Felkin 96 : 4 4 : 96 R = t-Bu R = Me R = Me, t-Bu ³ 97 : 3 (2) (3) ■ A problem Aldehydes 1 & 2 contain 2 stereocenters, each of which may influence the course of the addition process. For 1, the reaction is Felkin selective for all enolsilanes; however, for 2, this is not the case. Explain. For the answer see: Evans, JACS 1996, 118, 4322. (pdf) 1 2 Fischer Cram Cornforth Felkin Anh/Eisenstein Cieplak Tomoda ■ 1,2-Asymmetric Induction Models ■ 1,3-Asymmetric Induction Models ■ Merged 1,2- and 1,3-Asymmetric Induction ■ Unpredicted, highly selective carbonyl additions Mengel, A.; Reiser, O. Chem. Rev. 1999, 99, 1191-1223 Gung, B. W. Tetrahedron 1996, 52, 5263-5301 Ager, D. J.; East, M. B. Tetrahedron 1992, 48, 2803-2894 Reetz, M. T. Angew. Chem. Int. Ed. Engl. 1984, 23, 556-569 Morrison, J. D.; Mosher, H. S. Asymmetric Organic Reactions; Prentice Hall Inc.: 1971 Wipf, P.; Kim, Y. J. Am. Chem. Soc. 1994, 116, 11678-11688, ref. 1-5, 7