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Oxy anion-accelerated rearrangements

Citation

Baillargeon, David Joseph (1979) Oxy anion-accelerated rearrangements. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/9M01-KJ80. https://resolver.caltech.edu/CaltechTHESIS:05012015-142954149

Abstract

The alkali metal salts of 1,5-hexadien-3-ols undergo accelerated Cope rearrangements to the enolates of δ, ε-unsaturated carbonyl compounds. The generality of the rearrangement was investigated in numerous systems, particularly acyclic cases, and the effect of changes in substituents, counterions, solvents, and geometrical structures were noted and discussed. Applications of this methodology in synthesis included the synthesis of the insect pheromone frontalin, the preparation of selectively monoprotected 1,6-dicarbonyl compounds from 4-methoxy- and 4-phenylthio-1,5-hexadien-3-ols, and the construction of complex ring structures such as a D-homo-estratetraenone derivative.

Thermochemical estimates of the energetics of anionpromoted alkoxide fragmentations were made, and in all cases heterolytic cleavage was favored over hemolytic cleavage by 8.5-53 kcal/mol. The implication of these and other thermochemical estimates is that the anionic oxy-Cope rearrangement occurs via a concerted mechanism rather than a dissociation-recombination process. The concepts of anion-induced bond weakening were successfully applied to an accelerated [1,3]-shift of a dithiane fragment in a cyclohexenyl system. Trapping experiments demonstrated that > 85% of the [1,3]-shift occurred within a solvent cage. Attempts at promoting an intramolecular ene reaction using the potassium salts of 2,7-octadien-1-o1 and 2,8-nonadien-1-o1 were unsuccessful. A general review of anion-promoted bond reorganizations and anion substituent effects is also presented.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:oxy-Cope rearrangement, Cope rearrangement, [3,3] rearrangment, [1,3] rearrangment, alkoxide fragmentation, synthetic method
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Evans, David A.
Thesis Committee:
  • Unknown, Unknown
Defense Date:23 January 1979
Record Number:CaltechTHESIS:05012015-142954149
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:05012015-142954149
DOI:10.7907/9M01-KJ80
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8842
Collection:CaltechTHESIS
Deposited By: Benjamin Perez
Deposited On:01 May 2015 21:56
Last Modified:21 Dec 2019 01:46

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