Ir-Catalyzed Oxidative Desymmetrization of meso-Diols
摘要:
The catalytic oxidative desymmetrization of meso-diols was realized using a chiral iridium catalyst. In particular, the reaction is effective for the cyclic diols to give the corresponding hydroxy ketones in high chemical yields with high ee's. With this reaction as a key step, a short-step synthesis of common intermediate of ottelione and scyphostatin was achieved.
Aerobic oxidative desymmetrization of meso-diols with bifunctional amidoiridium catalysts bearing chiral N-sulfonyldiamine ligands
摘要:
Asymmetric aerobic oxidation of a range of meso- and prochiral diols with chiral bifunctional Ir catalysts is described. A high level of chiral discrimination ability of Cp*Ir complexes derived from (S,S)-1,2-diphenylethylenediamine was successfully demonstrated by desymmetrization of secondary benzylic diols such as cis-indan-1,3-diol and cis-1,4-diphenylbutane-1,4-diol, providing the corresponding (R)-hydroxyl ketones with excellent chemo- and enantioselectivities. Enantiotopic group discrimination in oxidation of symmetrical primary 1,4- and 1,5-diols gave rise to chiral lactones with moderate ees under similar aerobic conditions. (C) 2014 Elsevier Ltd. All rights reserved.
Acylative Desymmetrization of Cyclic <i>meso</i>-1,3-Diols by Chiral DMAP Derivatives
作者:Hiroki Mandai、Tsubasa Hironaka、Koichi Mitsudo、Seiji Suga
DOI:10.1246/cl.200809
日期:2021.3.5
An efficient enantioselective acylative desymmetrization of cyclic meso-1,3-diols was developed by using a chiral DMAP derivative 1e having a 1,1′-binaphthyl unit. The reactions required only 0.5 m...
quantitative reduction of aromatic aldehydes, ketones, diketones and oxo aldehydes to alcohols by use of TiCl3/NH3 in aqueous methanol solution is reported. The reducing system distinguishes between different classes of aldehydes and/or ketones, and many functionalities that usually do not survive under reducing conditions are tolerated well. The concept of reversal of chemoselectivity has also been developed
Chiral Ru(salen)(nitrosyl) complex 1 is a useful catalyst for asymmetric aerobic oxidation of alcohols under photo-irradiation. In this study, it was found that addition of β-hydroxy ketone or 1,3-diketone had a significant influence on its asymmetric catalysis. For example, the addition of 1,3-bis(p-bromophenyl)propane-1,3-dione 9 improved the relative reaction ratio in kinetic resolution of simple
Asymmetric monobenzoylation reactions of cyclic meso-1,3- and 1,4-diols were catalyzed by a phosphinite derivative of quinidine to afford the corresponding monobenzoylated diol with good yield and enantioselectivity. [reaction: see text]
Chemoselective formation of cyclo-aliphatic and cyclo-olefinic 1,3-diols <i>via</i> pressure hydrogenation of potentially biobased platform molecules using Knölker-type catalysts
作者:Christian A. M. R. van Slagmaat、Teresa Faber、Khi Chhay Chou、Alfonso J. Schwalb Freire、Darya Hadavi、Peiliang Han、Peter J. L. M. Quaedflieg、Gerard K. M. Verzijl、Paul L. Alsters、Stefaan M. A. De Wildeman
DOI:10.1039/d1dt01252e
日期:——
Hemicellulose-derived five-membered cyclic ketones are strategic precursors for sustainable 1,3-diol building blocks, and bifunctional iron catalysts provide unprecedented chemoselectivity in hydrogenation toward aliphatic and olefinic structures.