143505-39-9Relevant articles and documents
Achiral dihydroxylation of olefins by osmate (OsO4 2-) stabilised on nanocrystalline magnesium oxide
Choudary, Boyapati M.,Jyothi, Karangula,Kantam, Mannepalli L.,Sreedhar
, p. 45 - 48 (2004)
A recoverable and reusable new heterogeneous AP-Mg-OsO4 catalyst was designed and developed for the first time via a counterionic stabilisation of OsO42- with Mg2+ present on the corner or edge of nanocrystalline MgO. AP-Mg-OsO4 catalysed the dihydroxylation of olefins to afford diols with excellent yields in the presence of N-methylmorpholine N-oxide for the first time. The absence of osmium and no progress of the dihydroxylation reaction with the filtrate samples withdrawn periodically during the reaction rule out the leaching of osmium unambiguously and provide evidence for the heterogeneity of the reaction. Identification of surface intermediate species by XPS and TGA-DTA-mass thermography gives an insight into the mechanism of the dihydroxylation reaction.
Bromoacetone: A new protective group for 1,2-diols cleavable with zinc
Chandrasekhar,Srinivas,Suresh Kumar,Muralidhar
, p. 1147 - 1152 (2000)
Bromoacetone has been utilized for the first time as an excellent protective group for 1,2-diols that can be cleaved under neutral conditions viz., refluxing in Zn-MeOH.
Base-Mediated Cascade Aldol Addition and Fragmentation Reactions of Dihydroxyfumaric Acid and Aromatic Aldehydes: Controlling Chemodivergence via Choice of Base, Solvent, and Substituents
Ward, George,Liotta, Charles L.,Krishnamurthy, Ramanarayanan,France, Stefan
, p. 14219 - 14233 (2018/10/24)
The diester derivative of dihydroxyfumaric acid (DHF) has been used exclusively as an electrophile in organic synthesis. However, the synthetic utility of DHF's nucleophilic reactivity, contained in the ene-diol moiety, has been underexplored. Inspired by recently observed pH-dependent chemodivergent nucleophilic aldol reactions of dihydroxyfumarate (DHF2-) with glyoxylate and formaldehyde, we report herein the control and synthetic application of base-controlled chemodivergent reactions between dihydroxyfumarate and aromatic and heteroaromatic aldehydes. With hydroxide as the base in a predominantly aqueous medium, aldol addition followed by deoxalation occurs to provide various 3-aryl-2,3-dihydroxypropanoic acids. With triethylamine as the base in THF, 1-aryl-2,3-dihydroxypropanones are the products of the reaction. In order to understand the difference in reactivity between DHF, its dicarboxylate, and its dimethyl ester, we undertook computational and experimental studies that provide a rationale as to why the dihydroxyfumarate (DHF2-) is a nucleophile while the corresponding diester reacts as an electrophile.
Enantioselective bio-hydrolysis of various racemic and meso aromatic epoxides using the recombinant epoxide hydrolase Kau2
Zhao, Wei,Kotik, Michael,Iacazio, Gilles,Archelas, Alain
, p. 1895 - 1908 (2015/06/02)
Abstract Epoxide hydrolase Kau2 overexpressed in Escherichia coli RE3 has been tested with ten different racemic and meso α,β-disubstituted aromatic epoxides. Some of the tested substrates were bi-functional, and most of them are very useful building blocks in synthetic chemistry applications. As a general trend Kau2 proved to be an extremely enantioselective biocatalyst, the diol products and remaining epoxides of the bioconversions being obtained - with two exceptions - in nearly enantiomerically pure form. Furthermore, the reaction times were usually very short (around 1 h, except when stilbene oxides were used), and the use of organic co-solvents was well tolerated, enabling very high substrate concentrations (up to 75 g/L) to be reached. Even extremely sterically demanding epoxides such as cis- and trans-stilbene oxides were transformed on a reasonable time scale. All reactions were successfully conducted on a 1 g preparative scale, generating diol- and epoxide-based chiral synthons with very high enantiomeric excesses and isolated yields close to the theoretical maximum. Thus we have here demonstrated the usefulness and versatility of lyophilized Escherichia coli cells expressing Kau2 epoxide hydrolase as a highly enantioselective biocatalyst for accessing very valuable optically pure aromatic epoxides and diols through kinetic resolution of racemates or desymmetrization of meso epoxides.
