Remarkable generality in scope of new C9-benzoylcupreines bearing electron-withdrawing substituents for the nitroaldol condensation with fluoromethyl ketones is presented. Both tri- and difluoromethyl ketones provided excellent levels of stereoinduction (ee 76–99%) under mild reaction conditions and low loading of catalyst (1–5 mol%).
A deuterium‐labelingreaction of nitroalkanes in deuterium oxide and the subsequent nitroaldol reaction have been accomplished under basic and organocatalytic conditions to provide the deuterium‐labeled β‐nitroalcohols in high yields and high deuterium contents. β‐Deuterated β‐nitroalcohols could be smoothly obtained from the reaction of nitroalkanes and various electrophiles using the easily‐removal
We report herein a strategy to afford a multicomponent catalyticenantioselectivesynthesis of β-substituted isoxazolidin-5-ones via a KMC process promoted by a suited cupreine used as bifunctional organocatalyst. The hydroxamic acid component, with a sterically hindered amide moiety, proved to be key for the successful formation and transformation of the obtained original N-amide isoxazolidin-5-ones
An organo-catalyzed Henry reaction, applied to an alpha-keto ester, has allowed the enantioselective synthesis of SSR 241586, a 2,2-disubstituted morpholine active in the treatment of schizophrenia and irritable bowel syndrome (IBS).
Development of C-6′-modified quinine-derived phase-transfer catalysts and their application in the enantioselective α-hydroxylation of β-dicarbonyl compounds
We have developed C-6'-modified quinine quaternary ammonium salts as phase transfer catalysts for alpha-hydroxylation of beta-dicarbonyl compounds. The quinine quaternary ammonium salts, which was modified at C-6' and the N atom, had good activity for alpha-hydroxylation of B-dicarbonyl compounds. By using 5 mol % of 6-hydroxyl-N-(4'-fluoro-2'-trifluoromethyl)quinine quaternary ammonium salt as the organocatalyst, cumene hydroperoxide as the oxidant, toluene as the solvent, and 50% K2HPO4 as the aqueous alkali at room, temperature, the yield and enantioselectivity of the alpha-hydroxylation of beta-keto esters were 95% and 88%, respectively. This catalytic system was also applicable for beta-keto amides (92% yield and 76% ee). (C) 2016 Elsevier Ltd. All rights reserved.