Organic Chemistry Innovators - Woodward, Nicolaou, Pauling

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R.B. Woodward (1917-1979) • 1st modern synthetic organic chemist • Probably greatest organic chemist • 1965 Nobel Prize in Chemistry • “outstanding achievements in the art of organic synthesis • Also made VERY important observations in the development of the Woodward-Hoffman rules of ring closure • 1st step in the application of quantum mechanics to organic molecules • 1981 Nobel Prize in Chemistry (Roald Hoffmann)

R.B. Woodward (Early Career)

R.B. Woodward (Later Career)

R.B. Woodward

K.C. Nicolaou • Penn (1977-1989) • Scripps Research Institute and UC-San Diego (1989-present) • Modern day R.B. Woodward

K.C. Nicolaou Taxol • Isolated in 1967 from bark of Pacific yew tree • Lung, ovarian, breast, head and neck cancer 11 stereocenters => 211 = 2048 stereoisomers 2 rings & 1 bicyclic ring

K.C. Nicolaou Brevotoxin B • Neurotoxin that binds to voltage-gated sodium channels in nerve cells • Naturally found in Karenia brevis which are marine organisms typically found in fish 23 stereocenters => 223 = 8,400,000 stereoisomers 11 trans-fused rings 83 steps, 12 years 91% yield for each step but 0.043% total yield

K.C. Nicolaou Maitotoxin • Neurotoxin that binds to calcium channels • Naturally produced by Gambierdiscus toxicus which are marine organisms typically found in fish 94 stereocenters => 294 = 1.98 x 1028 stereoisomers 31 trans-fused rings

Atomic Orbitals

Linus Pauling (1901-1994) • Probably greatest chemist of the 20th century • Only person too win 2 unshared Nobel Prizes and only person to win 2 unrelated Nobel Prizes • 1954 – Chemistry • 1962 - Peace • “The Nature of the Chemical Bond” • Protein Structure • Antibody Structure and Process • Molecular cause of Sickle-cell anemia • Electronegativity • Resonance • Vitamin C and the Common Cold

The Periodic Table and Electronegativity

Common Bonding Situations Hydrogen 1 bond Carbon 4 bonds (neutral and 8 electrons) Reactive Carbon Species

Nitrogen 3 bonds and one unshared pair of electrons Other relatively stable species

Oxygen 2 bonds and 2 unshared electron pairs Other relatively stable species hydronium ion

Halogens 1 bond and 3 unshared electron pairs also 4 unshared pairs and negative charge

Table 2-6a, p. 51

Table 2-6b, p. 51

These are sigma (s) MOs: symmetrical about the internuclear axis

Organic Chemistry Innovators - Woodward, Nicolaou, Pauling

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