ABSTRACT
V. Electroreductive Cyclization A. Sterpurene B. Perhydrophenanthrene skeleton C. Quadrone D. Corey Lactone E. Capnellene diol, isoamijiol F. Guaiazulene, dihydrojasmone, rosaprostol, valeranone, hirsutene, .0.9(12>-cap-
nellene VI. Reduction of Pyridinium Salts-Quinolizidine and Indolizidine Derivatives
VII. Mediated Processes A. Mitomycins B. Vitamin B12-mediated cyclizations: California red scale pheromone, PGF2a
precursor VIII. Organometallics
A. Cephalosporin derivative B. Dihydrocoryantheol, dihydroantirhine. and tacamonine
IX. Reduction of Aryl Chlorides: Acyl-CoA Cholesterol Acyltransferase-Tnhibitory Substances
mycinone B. [5 + 2)-Cycloaddition C. Pyrroloquinoline alkaloids: Discorhabdin C D. Vancomycin model studies
XI. Closing Remarks Acknowledgments References
I. INTRODUCTORY REMARKS
Organic chemists commonly think of redox processes as those involving changes in the oxidation state of a functional group~the conversion of a ketone to a secondary alcohol, or the reverse transformation, for example. Electrochemistry provides a variety of solutions to problems of this nature. One also associates the term "redox" with the more fundamental processes of adding or removing an electron. Exciting opportunities are revealed when one thinks in this manner, because in so doing, one quickly realizes that reactive intermediates are formed. Often they display reactivity patterns opposite to that of the starting material. The ,B-carbon of the radical anion derived from an a.,B-unsaturated ester, for example, displays nucleophilic rather than electrophilic character. Similarly, the cation radical derived via oxidation of an enol ether displays electrophilic behavior. Beyond this, and in a point that we believe is sometimes not recognized by nonelectrochemists, is the fact that electrochemistry provides the opportunity to make the carbon-carbon bond, or bonds between carbon and heteroatoms. That is, it provides the chemist with alternative and sometimes unique ways to build molecules. The chemistry described in this chapter provides an overview of some of the creative ways researchers have elected to use electrochemistry to synthesize naturally occurring molecules, ranging from structurally simple, to those of much complexity.
