D. A. Evans Carbocations: Stability Structure Chem 206 http://www.courses.fasharvardedu/-chem206/ Other Relevant Background Reading March, Advanced Organic Chemistry, 4th Ed. Chapter 5, pp165-174 Lowery Richardson, Mech. Theory in Org, Chem., 3rd Ed. pp Chemistry 206 383-412. Arnett, Hoeflich, Schriver in Reactive Intermediates Vol 3, Wiley, 1985 Chapter 5, p 189 Advanced Organic Chemistry Saunders, M. and H. A. Jimenez-Vazquez(1991). " Recent studies of carbocations Chem Rev 91: 375 Lecture number 30 Stang, P.J. (1978). " Vinyl Triflate Chemistry: Unsaturated Cations and Carbenes . Acc Chem. Res. 11: 107 Introduction to carbonium I Olah, G.A. and G. Rasul (1997). " Chemistry in superacids 26. From Kekule's tetravalent methane to five-, Six- and seven-coordinate protonated methanes Carbocation stabilization Acc.Chem.Res30(6):245-250 Walling, C (1983). "An Innocent Bystander Looks at the 2-Norbornyl Cation Carbocation Structures by X-ray Crystallography Acc. Chem. Res 16: 448 a Vinyl Allyl Carbonium Ions Exam Question Fall, 2001. The reaction illustrated was recently Snider and co-workers(Org Lett. 2001, 123, 569-572. Prov Reading Assignment for this Lecture nal drawings to support your answer Carey Sundberg, Advanced Organic Chemistry, 4th Ed Part A Chapter 5, Nucleophilic Substitution, 263-350 cH2C2,0°C Laube(1995). X-Ray Crystal Structures of Carbocations Stabilized by Bridging or Hyperconjugation. " Acc. Chem. Res 28, 399(pdf) Carey Sundberg-A, p 337: Provide mechanisms for the following reactions Olah, G A (1995). My search for carbocations and their role in chemistry (Nobel lecture). "Angew. Chem., Int. Ed. Engl. 34, 1393-1405.(CCB library Olah, G.A. (2001). 100 Years of Carbocations and their Significance Chemistry. "J. Org. Chem. 2001, 66, 5944-5957.(pdf HOAC/H2O HOAC/H2O Matthew d. shair Wednesday December 4. 2002http://www.courses.fas.harvard.edu/~chem206/ OH NH2 NaNO2 Me O Me Me R HOAc/H2O CHO EtAlCl2 OH NH2 CMe3 Me O Me R Me NaNO2 HOAc/H2O O CMe3 D. A. Evans Chem 206 Matthew D. Shair Wednesday, December 4, 2002 Reading Assignment for this Lecture: Other Relevant Background Reading Chemistry 206 Advanced Organic Chemistry Lecture Number 30 Introduction to Carbonium Ions ■ Carbocation Stabilization ■ Carbocation Structures by X-ray Crystallography ■ Vinyl & Allyl Carbonium Ions Carbocations: Stability & Structure March, Advanced Organic Chemistry, 4th Ed. Chapter 5, pp165-174. Lowery & Richardson, Mech. & Theory in Org, Chem., 3rd Ed. pp 383-412. Arnett, Hoeflich, Schriver in Reactive Intermediates Vol 3, Wiley, 1985, Chapter 5, p 189. Carey & Sundberg, Advanced Organic Chemistry, 4th Ed. Part A Chapter 5, "Nucleophilic Substitution", 263-350 . Walling, C. (1983). “An Innocent Bystander Looks at the 2-Norbornyl Cation.” Acc. Chem. Res. 16: 448. Olah, G. A. and G. Rasul (1997). “Chemistry in superacids .26. From Kekule's tetravalent methane to five-, six- and seven-coordinate protonated methanes.” Acc. Chem. Res. 30(6): 245-250. Saunders, M. and H. A. Jimenez-Vazquez (1991). “Recent studies of carbocations.” Chem. Rev. 91: 375. Stang, P. J. (1978). “Vinyl Triflate Chemistry: Unsaturated Cations and Carbenes.” Acc. Chem. Res. 11: 107. Olah, G. A. (1995). “My search for carbocations and their role in chemistry (Nobel lecture).” Angew. Chem., Int. Ed. Engl. 34, 1393-1405. (CCB library) Laube (1995). “X-Ray Crystal Structures of Carbocations Stabilized by Bridging or Hyperconjugation.” Acc. Chem. Res. 28,: 399 (pdf) Olah, G. A. (2001). “100 Years of Carbocations and their Significance in Chemistry.” J. Org. Chem. 2001, 66, 5944-5957. (pdf) Qumulative Exam Question Fall, 2001. The reaction illustrated below was recently reported by Snider and co-workers (Org. Lett. 2001, 123, 569-572). Provide a mechanism for this transformation. Where stereochemical issues are present, provide clear three dimensional drawings to support your answer. CH2Cl2, 0 °C Carey & Sundberg-A, p 337: Provide mechanisms for the following reactions