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Catalytic Asymmetric Total Syntheses of Quinine and Quinidine. Izzat T. Raheem , Steven N. Goodman, and Eric N. Jacobsen J. Am. Chem. Soc. 2004, 126, 3, 706 Presented by Michael Elbaum. Dr. Eric N. Jacobsen. Born February 22, 1960 B.S. New York University (1982) Ph.D. UCLA Berkeley (1986) - PowerPoint PPT Presentation
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Catalytic Asymmetric Total Syntheses of Quinine and
QuinidineIzzat T. Raheem, Steven N. Goodman, and Eric N. Jacobsen
J. Am. Chem. Soc. 2004, 126, 3, 706
Presented by Michael Elbaum
Dr. Eric N. JacobsenBorn February 22, 1960B.S. New York University (1982)Ph.D. UCLA Berkeley (1986)Postdoctoral Fellow MIT, Barry K. SharplessAssociate Professor University of IllinoisCurrently Sheldon Emery Professor of Chemistry,
HarvardDevelopment of new methods for organic synthesis
with an emphasis on asymmetric catalysis
Quinine & Quinidine Cinchona alkaloids have long been known for their medicinal properties; Antipyretic, antimalarial, analgesic and anti-inflammatory
Naturally occurs in the bark of cinchona trees
Correct connectivity was discovered by Rabe in 1907
First synthesis of quinine from quinotoxine by Rabe and Kindler in 1918
Woodward and Doering synthesizes quinotoxine in 1944
First stereoselective approach used by Uskokovic and Gutzwiller in 1978
First entirely stereoselective total synthesis of quinine by Stork in 2000
Quinine & Quinidine
Initial Approach
Initial Approach
Fragment A Synthesis: Honer-Wadsworth-Emmons (HWE)
Reversible reaction allows Thermodynamically Stable, (E) product
Fragment A Synthesis: Catalyzed Michael Addition
Fragment A Synthesis:Hydrogenation / Lactamization
Cis/Trans 1:1.7 converted to 3:1 with:
i. LDA, THF, -78o Cii. H2O/THF (5%), -78o C
Fragment A Synthesis:Wittig Olefination
Fragment A Synthesis:Alkylation
Fragment B Synthesis
Suzuki Coupling of A & B
Ligand Gift from Buchwald
Suzuki Cross-Coupling
Sharpless Asymmetric Dihydroxylation
ADmix-Beta = DHQD Admix-Alpha = DHQ
Epoxidation
CBz Removal / Intramolecular Sn2
Conclusion
5% total yieldLongest linear step is 13Quinine remains a target for total synthesis