Date of Award
Chemistry and Biochemistry
CC BY-NC-ND 4.0
Self-condensation of crotonaldehyde under base-catalyzed phase-transfer conditions leads to 4,6-dimethyl dihydropyrancarboxaldehyde or dihydro-o-tolualdehyde, depending only on the concentration of aqueous hydroxide used. Dihydro-o-tolualdehyde is formed when the hydroxide concentration is between 70% (17.5N) and 25% (6.25N). 4,6-Dimethyl dihydroyrancarboxaldehyde first appears at a hydroxide concentration 30% (7.5N) and it continues to be produced at concentrations as low as 5% (1.25N). The range, over which the product completely changes from one to the other, is small (30% NaOH to 25% NaOH). It appears that, as the hydroxide concentration decreases, the water concentration in the organic phase is sufficient to alter the action of the organic phase hydroxide from that of a base to that of a nucleophile. Mixed condensations using this phase-transfer technique are also reported. Self-condensation of senecioaldehyde under phase-transfer conditions leads to 4,6,6-trimethyl-1,3-cyclohexadienecarboxaldehyde. This product is used in an attempted synthesis of an isomer of (beta)-damascenone. Dihydrothiopyrans are reacted with methyl diethylphosphonoacetate in order to produce dienes suitable for use in Diels-Alder reactions. Several attempts using these dienes with maleic anhydride in a Diels-Alder type reaction are reported. A simple synthesis of N-chlorinated secondary amines, using commercial swimming pool bleach ((TURN)12.5% NaOCl), under phase-transfer conditions is reported. Source: Dissertation Abstracts International, Volume: 42-03, Section: B, page: 1022. Thesis (Ph.D.)--University of Windsor (Canada), 1981.
PILLON, DAVID WILLIAM., "PART I: PHASE-TRANSFER REACTIONS OF ENONES. PART II: SYNTHETIC APPLICATIONS OF DIHYDROTHIOPYRANS." (1981). Electronic Theses and Dissertations. 3011.