Date of Award
Chemistry and Biochemistry
Bryan J. Cowen, Ph.D.
Allenoates, Lewis base catalysis, Method development, Organic chemistry
Lewis base promoted cyclization of allenoates with electron deficient olefins open up the possibility to generate more complex organic structures. By generating more complex molecules, we are able to produce new compounds for biomedical and material applications. Both phosphine and amine Lewis bases offer interesting annulations with allenoates resulting in Lu or Morita–Baylis–Hillman type reactions. Once the Lewis base engages with the allenoate there can be several modes of nucleophilic reactivity that allows for the allenic ester to act as a two or three carbon synthon. The allenoate can then react with varying electron deficient olefins generating more complex molecules with high atom economy and few byproducts.
The development of complex small molecules using easy to obtain starting materials such as 1,4-naphthoquinone is a significant goal of this project. Current research has been focused on cyclizing 1,4-naphthoquinone with varying allenoate substituents using triphenylphosphine as the Lewis base. This method has proven successful with yields up to 90 % for 10 different allenic esters. To expand on the utility of the method 2- methyl-1,4-naphthoquionone and 2-hydroxy-1,4-napthoquinone were explored. 2-methyl1,4-naphthoquinone gives the target product with yields around 45%. 2-hydroxy-1,4- naphthoquinone also gives the target product with yields around 35%. 2-hydroxy-1,4- naphthoquionone also gives a Ramirez ylide derivative with yields around 25%.
The method was expanded to include amine promoted reactions of 1,4- naphthoquinones with allenoates. Several reaction conditions were attempted with promising results. Phosphine promoted reactions were also attempted with γ-substituted allenoates using 2-methyl-1,4-naphthoquinone as a coupling partner with extremely promising results toward a single product.
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Shoup, Nicole Marie, "Lewis Base Promoted Annulations of Allenoates with 1,4-Naphthoquinones" (2019). Electronic Theses and Dissertations. 1692.
Received from ProQuest
Nicole Marie Shoup