Task-specific ionic liquid and CO<sub>2</sub>-cocatalysed efficient hydration of propargylic alcohols to α-hydroxy ketones
作者:Yanfei Zhao、Zhenzhen Yang、Bo Yu、Hongye Zhang、Huanjun Xu、Leiduan Hao、Buxing Han、Zhimin Liu
DOI:10.1039/c5sc00040h
日期:——
Task-specific ionic liquid and CO2-cocatalysed efficient hydration of propargylic alcohols to α-hydroxy ketones.
特定任务离子液体和CO2共催化的高效合成炔丙醇水合成α-羟基酮。
α-Hydroxy Ketones as Masked Ester Donors in Brønsted Base Catalyzed Conjugate Additions to Nitroalkenes
作者:Iurre Olaizola、Teresa E. Campano、Igor Iriarte、Silvia Vera、Antonia Mielgo、Jesús M. García、José M. Odriozola、Mikel Oiarbide、Claudio Palomo
DOI:10.1002/chem.201705968
日期:2018.3.12
catalyst‐controlled enantioselective direct addition reaction of enolizable esters and related carboxylic acid derivatives to π electrophiles remains a difficult synthetic transformation. In this study, the suitability of α‐hydroxy ketones as ester equivalents capable of being activated by bifunctional Brønsted base catalysts in the context of conjugateaddition reactions to nitroolefins is demonstrated
A carbon dioxide-promoted and silver acetate-catalyzed hydration of propargylicalcohols for the efficient synthesis of tertiary α-hydroxy ketones has been developed. The reaction is proposed to proceed via a tandem process of carbon dioxide incorporation into propargylicalcohols and subsequent hydrolysis.
Cross-linked copolymers which are obtained by polymerising a neutral diluent monomer or monomers, a monomer or monomers bearing a center of permanent positive charge, and a bifunctional and/or trifunctional cross-linking agent, are suitable for use in contact lenses. Process for producing them by copolymerisation, contact lens material comprising them, contact lenses made of them and processes for producing contact lenses from them.
The controlled aldol condensation between an aliphatic ketone and an acetaldehyde equivalent remains a challenge. One solution to this evergreen problem consists of the nucleophilic addition of acetylene to the ketone and the subsequent isomerization of the resulting 3-hydroxy-1-alkyne to the corresponding 2-alkenal. So far, however, the latter step could only be executed with acid-insensitive substrates. We now present a milder, three-step method which extends the scope of the procedure considerably. In the first step, the 3-hydroxy-1-alkynes are converted into 2-propynyl ethylene glycol monoethers; these then undergo base-catalyzed cyclization to give the dihydro-1,4-dioxepins, which are hydrolyzed in acidic medium in the third and final step.