lecture 6 carbanionic synthons unit 2 outlineweb.mit.edu/5.511/www/10-19-07.pdf · 10/19/2007 ·...
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Massachusetts Institute of TechnologyOrganic Chemistry 5.511
October 19, 2007Prof. Rick L. Danheiser
Carbanionic Synthons
Lecture 6
Reading Assignment
Background: Clayden et al. Sections of Chapters 9, 21, and 26
Carey and Sundberg Part B, Chapters 1, 7 (Sections 7.1, 7.2, and 7.3.1), and 8 (Section 8.1) Note: some stereochemical features of this chemistry will not be covered until later units
1. Metalation with base (deprotonation) 2. Oxidative addition (reductive metalation) 3. Halogen-metal exchange 4. Transmetalation 5. Addition to π-bonds 6. Fragmentation and cleavage
Introduction to General Reactivity and Overview ofGeneral Methods for the Generation of Carbanionic Synthons
Unit 2 Outline
Case Study
Total Synthesis of Cecropia Juvenile HormoneKondo, K.; Negishi, A.; Matsui, K.; Tsunemoto, D.; Masamune, S. Chem. Commun. 1972, 1311Stotter, P. L.; Hornish, R. E. J. Am. Chem. Soc. 1973, 95, 4444Demoute, J. P.; Hainaut, D. Toromanoff, E. C. R. Acad. Sci., Ser. C 1973, 277, 49
CO2Me
O
S
OHS
S
S
O
OHCl
+
+
OH
1) Li, EtNH2, -78 °C2) RaNi, EtOH Δ 4 h
Hyalophora cecropia
Henry Gilman1893-1986
"Henry Gilman: American Pioneer in the Rise of Organometallic Chemistry in Modern Science and Technology" Eisch, J. J. Organometallics 2002, 21, 5439
Umpolung Reversal of polarity