59367-33-8Relevant academic research and scientific papers
Direct, high-yielding, one-step synthesis of vic-diols from aryl alkynes
Ramachandran, P. Veeraraghavan,Drolet, Michael P.
, p. 967 - 970 (2018)
An unprecedented, high yielding, direct, one-step synthesis of vic-diols from alkynes has been developed via metal-free, open-to-air dihydroboration with ammonia borane. The electronics of the alkyne and the reaction stoichiometry are critical for obtaining optimal yields of the 1,2-diol.
A recyclable dendritic osmium catalyst for homogeneous dihydroxylation of olefins
Fujita, Ken-Ichi,Yamazaki, Manabu,Ainoya, Taku,Tsuchimoto, Teruhisa,Yasuda, Hiroyuki
experimental part, p. 8536 - 8543 (2010/11/18)
A series of osmate (OsO42-) core dendrimers was prepared by an ion-exchange technique through the mixing of K 2OsO4 and a bis(quaternary ammonium bromide) core dendrimer, which consisted of poly(benzyl ether) dendron. By employing an osmate core dendrimer as a homogeneous catalyst, dihydroxylation reactions of olefins proceeded rapidly, and the dendritic osmium catalyst was recovered by reprecipitation and then reused. Furthermore, a dendritic effect on the recyclability of a catalyst was observed. In the case of asymmetric dihydroxylation reactions, the corresponding diol was obtained in a high chemical yield with a fair enantiomeric excess (ee). In this case, not only the dendritic osmium catalyst but also the chiral ligand could be recovered by reprecipitation and reused efficiently up to five times.
Osmium-catalyzed asymmetric dihydroxylation by carbon dioxide-activated hydrogen peroxide and N-methylmorpholine
Balagam, Bharathi,Mitra, Ranjan,Richardson, David E.
, p. 1071 - 1075 (2008/09/18)
An improved process has been developed for the osmium-catalyzed dihydroxylation of olefins via in situ formation of NMO from NMM using CO2 catalysis and H2O2. All olefins examined were selectively cis-dihydroxylated to their corresponding diols in good to excellent yields, and by the use of chiral ligands, high enantiomeric excesses were obtained.
Osmium-catalyzed dihydroxylation of alkenes by H2O2 in room temperature ionic liquid co-catalyzed by VO(acac)2 or MeReO3
Johansson, Mikael,Lindén, Auri A.,B?ckvall, Jan-E.
, p. 3614 - 3619 (2007/10/03)
Room temperature ionic liquid [bmim]PF6 was used to immobilize a bimetallic catalytic system for H2O2-based dihydroxylation of alkenes. Osmium tetroxide was used as the substrate-selective catalyst with either VO(acac)2 or MeReO 3 as co-catalyst. The latter serve as an electron transfer mediator (ETM) and activates H2O2. For an increased efficiency N-methylmorpholine is required as an additional ETM in most cases. A range of alkenes were dihydroxylated using this robust bimetallic system and it was demonstrated that for some of the alkenes the catalytic system can be recycled and used up to five times.
The acid accelerated ruthenium-catalysed dihydroxylation. Scope and limitations
Plietker, Bernd,Niggemann, Meike,Pollrich, Anja
, p. 1116 - 1124 (2007/10/03)
Recently, we discovered a significant rate acceleration in RuO 4-catalysed dihydroxylations of olefins by addition of Broensted-acids resulting in a reduction of the catalyst loading to only 0.5 mol%. The present paper gives a full account on the optimisation protocol that led to the discovery of the beneficial influence of protic acids. A strong focus is set on the detailed description of the influence of different reaction parameters on both reactivity and selectivity. In the second part an intense investigation of scope and limitations will be presented. The results provided in this manuscript might lead to a deeper understanding of competing processes that influence the selectivity in RuO4-catalysed dihydroxylations.
An improved protocol for the RuO4-catalyzed dihydroxylation of olefins
Plietker, Bernd,Niggemann, Meike
, p. 3353 - 3356 (2007/10/03)
(Matrix Presented) Dihydroxylation under ruthenium catalysis provides an easy access to syn-diols, although overoxidation is a common side reaction. Furthermore, the high catalyst loadings offset the lower price of ruthenium compared to osmium. In this paper, we present an improved protocol for the RuO4-catalyzed syn-dihydroxylation using only 0.5 mol % catalyst under acidic conditions. A variety of olefins can be hydroxylated in good to excellent yields with only minor formation of side products.
Microencapsulation of osmium tetroxide in polyurea
Ley, Steven V.,Ramarao, Chandrashekar,Lee, Ai-Lan,stergaard, Niels,Smith, Stephen C.,Shirley, Ian M.
, p. 185 - 187 (2007/10/03)
(Matrix presented) Osmium tetroxide has been microencapsulated in a polyurea matrix using an in situ interfacial polymerization approach. These microcapsules have been effectively used as recoverable and reusable catalysts in the dihydroxylation of olefins.
Osmium-Catalyzed Dihydroxylation of Olefins in Acidic Media: Old Process, New Tricks
Dupau, Philippe,Epple, Robert,Thomas, Allen A.,Fokin, Valery V.,Sharpless, K. Barry
, p. 421 - 433 (2007/10/03)
A screen of over 500 diversely functionalized additives in osmium-catalyzed dihydroxylation has uncovered that electron-deficient olefins are converted into the corresponding diols much more efficiently when the pH of the reaction medium is maintained on the acidic side. Further studies have identified citric acid as the additive of choice, for it allows preparation of very pure diols in yields generally exceeding 90%. As described here, a much wider range of olefin classes can now be successfully dihydroxylated. The process is experimentally simple, in most cases involving little more than dissolving the reactants in water or a waler/tertbutyl alcohol mixture, stirring them, and filtering off the pure diol product.
OsO(4) in ionic liquid [Bmim]PF(6): a recyclable and reusable catalyst system for olefin dihydroxylation. remarkable effect of DMAP.
Yao, Qingwei
, p. 2197 - 2199 (2007/10/03)
[reaction: see text] The combination of the ionic liquid [bmim]PF(6) and DMAP provides a most simple and practical approach to the immobilization of OsO(4) as catalyst for olefin dihydroxylation. Both the catalyst and the ionic liquid can be repeatedly recycled and reused in the dihydroxylation of a variety of olefins with only a very slight drop in catalyst activity.
Osmium-catalyzed asymmetric dihydroxylation of olefins by H2O2 using a biomimetic flavin-based coupled catalytic system
Jonsson,Faernegardh,Baeckvall
, p. 1365 - 1371 (2007/10/03)
Selective cis-dihydroxylation of olefins with the aid of a triple catalytic system using H2O2 as the terminal oxidant has been developed. In this process Os(VI) is recycled to Os(VIII) by a coupled electron-transfer-mediator system based on N-methylmorpholine and a biomimetic flavin, leading to a mild and selective electron transfer. Aliphatic, aromatic, and functionalized olefins were successfully cis-dihydroxylated, employing the triple catalytic system. The present biomimetic catalytic system works well in asymmetric dihydroxylation and gave optically active diols in good isolated yields and high enantiomeric excesses (up to 99% ee).
