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Investigation of the nitronate Nazarov cyclization
Doue, Alyssa Jane
Date: 2014
Type: Text
Abstract:
The Nazarov cyclization is a common synthetic tool in the synthesis of cyclopentenone rings. The reaction is characterized by a divinyl ketone starting reagent that undergoes a 4π-electron electrocyclization after addition of a Lewis/Brønsted acid; forming the cyclopentadienyl cation that undergoes cyclization. An extension of this methodology involves using a divinyl imine starting reagent. This cyclization is less favoured due to the electron donating ability of the nitrogen atom, causing the pentadienyl cation to be relatively stable and unwilling to undergo cyclization. To improve this cyclization, the imine is replaced with the electron withdrawing nitronate functionality. It is hypothesized that by doing so the addition of an acid will form the cyclopentadienyl cation that will readily undergo Nazarov cyclization. The synthesis of an aryl vinyl silyl nitronate was optimized and the compound was tested with a number of different acid catalysts to determine if the nitronate Nazarov cyclization is possible.
Description:
x, 104, [70] leaves : ill. (some col.) ; 29 cm.
Includes abstract and appendices.
Includes bibliographical references (leaves 94-104).