111004-04-7Relevant articles and documents
Stereoselective Synthesis of Optically Active α-hydroxy Ketones and anti-1,2-diols via Asymmetric Transfer Hydrogenation of Unsymmetrically Substituted 1,2-diketones
Koike, Takashi,Murata, Kunihiko,Ikariya, Takao
, p. 3833 - 3836 (2000)
Formula Represented A well-defined chiral Ru catalyst RuCl(N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine)(η6-arene) effectively promotes asymmetric transfer hydrogenation of 1-aryl-1,2-propanedione with HCOOH/N(C2H5)3, leading preferentially to optically active 1-aryl-2-hydroxy-1-propanone with up to 99% ee and 89% yield at 10°C. The reaction at 40°C gives anti-1-aryl-1,2-propanediol with up to 95% ee and 78% yield. This is a highly efficient procedure for the synthesis of optically active anti-diols.
Orthogonally protected 1,2-diols from electron-rich alkenes using metal-free olefin syn-dihydroxylation
Colomer, Ignacio,Barcelos, Rosimeire Coura,Christensen, Kirsten E.,Donohoe, Timothy J.
, p. 5880 - 5883 (2016/11/29)
A new method for the stereoselective metal-free syn-dihydroxylation of electron-rich olefins is reported, involving reaction with TEMPO/IBX in trifluoroethanol (TFE) or hexafluoroisopropanol (HFIP) and the addition of a suitable nucleophile. Orthogonally
Oxidative hydroxylation mediated by alkoxysulfonium ions
Ashikari, Yosuke,Nokami, Toshiki,Yoshida, Jun-Ichi
supporting information; experimental part, p. 938 - 941 (2012/05/05)
Oxidative hydroxylation of toluene derivatives via alkoxysulfonium ion intermediates was achieved by integration of anodic oxidation and hydrolysis to give benzyl alcohols which are also susceptible to oxidation. Alkenes were also oxidized to give 1,2-diols without overoxidation. The integration of electrochemical oxidative cyclization and hydrolysis was achieved using alkenes bearing a nitrogen atom in an appropriate position to give cyclic β-amino-substituted alcohols.
Metal-free dihydroxylation of alkenes using cyclobutane malonoyl peroxide
Jones, Kevin M.,Tomkinson, Nicholas C. O.
experimental part, p. 921 - 928 (2012/02/16)
Cyclobutane malonoyl peroxide (7), prepared in a single step from the commercially available diacid 6, is an effective reagent for the dihydroxylation of alkenes. Reaction of a chloroform solution of 7 with an alkene in the presence of 1 equiv of water at 40 °C followed by alkaline hydrolysis leads to the corresponding diol (30-84%). With 1,2-disubstituted alkenes, the reaction proceeds with syn-selectivity (3:1 → 50:1). A mechanism consistent with experimental findings is proposed, which is supported by deuterium and oxygen labeling studies and explains the stereoselectivity observed. Alternative reaction pathways that are dependent on the structure of the starting alkene are also described leading to the synthesis of allylic alcohols and γ-lactones.
A new enzymatic approach to (R)-Tamsulosin hydrochloride
Acetti, Daniela,Brenna, Elisabetta,Fuganti, Claudio
, p. 488 - 492 (2007/10/03)
An enantioselective baker's yeast mediated approach to the pharmacologically active (R)-enantiomer of Tamsulosin hydrochloride is reported.
Ruthenium- and lipase-catalyzed DYKAT of 1,2-diols: an enantioselective synthesis of syn-1,2-diacetates
Edin, Michaela,Martin-Matute, Belen,Baeckvall, Jan-E.
, p. 708 - 715 (2007/10/03)
Regio- and stereoselective lipase-catalyzed kinetic resolutions were investigated for some unsymmetrical, secondary/secondary syn-diols. Candida antarctica lipase B-catalyzed transesterifications of a few aryl/alkyl- and alkyl/alkyl 1,2-diols were coupled
Radical α-C-H hydroxyalkylation of ethers and acetal
Yoshimitsu, Takehiko,Arano, Yoshimasa,Nagaoka, Hiroto
, p. 2342 - 2345 (2007/10/03)
(Chemical Equation Presented) Ethers and an acetal were found to undergo direct intermolecular addition to aldehydes under the Et3B/air conditions. This study presents a very unique and simple means for the radical α-C-H hydroxyalkylation of oxygen-containing compounds.
Spontaneous Hydrolysis Reactions of cis- and trans-β-Methyl-4-methoxystyrene Oxides (Anethole Oxides): Buildup of frans-Anethole Oxide as an Intermediate in the Spontaneous Reaction of cis-Anethole Oxide
Mohan, Ram S.,Gavardinas, Kostas,Kyere, Sampson,Whalen, Dale L.
, p. 1407 - 1413 (2007/10/03)
Rates and products of the reactions of trans- and cis-β-methyl-4-methoxystyrene oxides (1 and 2) (anethole oxides) and β,β-dimethyl-4-methoxystyrene oxide (3) in water solutions in the pH range 4-12 have been determined. In the pH range ca. 8-12, each of these epoxides reacts by a spontaneous reaction. The spontaneous reaction of trans-anethole oxide (1) yields ca. 40% of (4-methoxyphenyl)acetone and 60% of 1-(4-methoxyphenyl)-1,2-propanediols (erythro:threo ratio ca. 3:1). The spontaneous reaction of cis-anethole oxide is more complicated. The yields of diol and ketone products vary with pH in the pH range 8-11, even though there is not a corresponding change in rate. These results are interpreted by a mechanism in which 2 undergoes isomerization in part to the more reactive trans-anethole oxide (1), which subsequently reacts by acid-catalyzed and/or spontaneous reactions, depending on the pH, to yield diol and ketone products. The buildup of the intermediate trans-anethole oxide in the spontaneous reaction of cis-anethole oxide was detected by 1H NMR analysis of the reaction mixture. Other primary products of the spontaneous reaction of 2 are (4-methoxyphenyl)acetone (73%) and theo-1-(4-methoxyphenyl)-1,2-propanediol (ca. 3%). The rates and products of the spontaneous reaction of 2 and its β-deuterium-labeled derivative were determined, and the lack of significant kinetic and partitioning deuterium isotope effects indicates that the isomerization of 2 to ketone and to trans-anethole oxide must occur primarily by nonintersecting reaction pathways.
Hindered organoboron groups in organic chemistry. 30. The production of erythro-1,2-diols by the condensation of dimesitylboron stabilised carbanions with aromatic aldehydes
Pelter,Peverall,Pitchford
, p. 1085 - 1094 (2007/10/03)
The condensation of dimesitylboron stabilised carbanions with a variety of aromatic aldehydes followed by in situ oxidation at low temperature, is a unique, highly stereoselective, direct and general process yielding predominantly erythro-1,2-diols.
Side-chain fragmentation of arylalkanol radical cations. Carbon-carbon and carbon-hydrogen bond cleavage and the role of α- and β-OH groups
Baciocchi, Enrico,Bietti, Massimo,Putignani, Lorenza,Steenken, Steen
, p. 5952 - 5960 (2007/10/03)
A product analysis and kinetic study of the one-electron oxidation of a number of 1-arylpropanols, 1,2-diarylethanols, and some of their methyl ethers by potassium 12-tungstocobaltate(III) (abbreviated as Co(III)W) in aqueous acetic acid was carried out and complemented by pulse radiolysis experiments. The oxidations occur via radical cations which undergo side-chain fragmentation involving the C(α)-H and/or C(α)-C(β) bond. With 1-(4-methoxyphenyl)-2-methoxypropane (1), only deprotonation of the radical cation is observed. In contrast, removing the ring methoxy group leads to exclusive C-C bond cleavage in the radical cation. Replacing the side-chain β-OMe by β-OH, the radical cation undergoes both C-C and C-H bond cleavage, with both pathways being base catalyzed. C-C bond breaking in the radical cation is also enhanced by an α-OH group, as shown by 1-(4-methoxyphenyl)-2,2-dimethyl-1-propanol (7), where this pathway, which is also base catalyzed, is the only one observed. Interestingly, α- and β-OH groups exhibit a very similar efficiency in assisting the C-C bond cleavage route in the radical cations, as is evident from the kinetic and products study of the oxidation of 1-phenyl-2-(4-methoxyphenyl)ethanol (5) and 1-(4-methoxyphenyl)-2-phenylethanol (6) by Co(III)W, and from pulse radiolysis experiments on 5 and 6. C-C bond cleavage is the main reaction for both radical cations which exhibit a very similar rate of fragmentation (k = 2.0 and 3.2 x 104 s-1, respectively). In both fragmentation reactions a small solvent isotope effect, k(H2O)/k(D2O) (1.4 for 5.+ and 1.2 for 6.+) and negative activation entropies are observed. These data suggest that a key role in the assistance by α- or β-OH groups to C-C bond cleavage is played by hydrogen bonding or specific solvation of these groups. The kinetic study of the oxidations promoted by Co(III)W has also shown that when only one group, OH or OMe, is present in the side chain (either on C(α) or C(β)), the fragmentation step or both the electron transfer and fragmentation steps contribute to the overall oxidation rate. However, with an OH group on both carbons of the scissile bond, as in 1-(4-methoxyphenyl)-1,2-propanediol (9), the rate of C-C bond cleavage is so fast that the electron transfer step becomes rate determining.
