Advices For Studying Organic Chemistry

Cortisone (R. B. Woodward): an antiinflammatory agent.

4) Prostaglandins F 2 α and E 2 (E. J. Corey): members of a family of hormones that

mediate blood pressure, smooth muscle contraction, and inflammation (Section

13.11D).

5) Vitamin B 12 (A. Eschenmoser and R. B. Woodward): used in the production of

blood and nerve cells (Section 4.20).

6) Taxol (K. C. Nicolaou): a potent cancer chemotherapy agent.

13.1 INTRODUCTION

1. Species that have a p orbital on an atom adjacent to a double bond:
   
   
   1. The p orbital may have a single electron as in the allyl radical (CH 2 =CHCH 2 •).
   
   
   2. The p orbital may be vacant as in the allyl cation (CH 2 =CHCH 2 +).
   
   
   3. The p orbital may contain a pair of electrons as in the allyl anion
      (CH 2 =CHCH 2 :–).
   
   
   4. It may be the p orbital of another double bond as in 1,3-butadiene
      (CH 2 =CH–CH=CH 2 ).
   
   
   
   


2. Conjugated unsaturated systems: systems that have a p orbital on an atom
   adjacent to a double bond ––– molecules with delocalized π bonds.^


3. Conjugation gives these systems special properties:
   
   
   1. Conjugated radicals, ions, or molecules are more stable than nonconjugated
      ones.
   
   
   2. Conjugated molecules absorb energy in the ultraviolet and visible regions of the
      electromagnetic spectrum.
   
   
   3. Conjugation allows molecules to undergo unusual reactions.
   
   
   
   

13.2 ALLYLIC SUBSTITUTION AND THE ALLYL RADICAL