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This research explores the synthesis of hemiketals through the enol ether attack on cationic ketenes for functionalized aldehyde production. Starting from alkoxyhomoallylic ynol ethers, we aimed to generate hemiketals; however, the reactions primarily yielded hydrolysis products. Various approaches utilizing solid acids and other non-aqueous catalysts were tested, but did not yield the desired cyclic products. This study highlights the challenges in synthesizing hemiketals and offers insights into potential avenues for further research in synthetic organic chemistry.
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Development of Synthetic Tools Using Ynol Ether Ionic Chemistry Benoit Daoust, Département de Chimie-Biologie, Université du Québec à Trois-Rivières, Trois-Rivières, Québec G9A 5H7 Enol ether attack on cationic ketenes ; formation of functionalized aldehydesand hemiketals: We investigated the possibility of producing hemiketals5 from alkoxyhomoallylicynol ethers 2. Alcohols 1a and 1b were first prepared. Ynolethers 2were prepared from alcohols 1a and 1b. Ynol ethers 2 were then reacted with a source of non-nucleophilic H+ (“solid acid” resin ) in the hope of producing a hemiketal (such as 5). Only hydrolysis products 6and 7 were isolated, no cyclization product could be observed. Using other “non-aqueous” acids (PhCOOH, TsOH, …) and HgO, Hg(OAc)2 or Ru(p-cymene)Cl2as catalysts led to the same undesired hydrolysis products. October2010 ACS PRF# 46293-B1
