106-25-2Relevant articles and documents
Selective Reduction of C=O in α,β-Unsaturated Carbonyls through Catalytic Hydrogen Transfer Reaction over Mixed Metal Oxides
Sonavane, Sachin U.,Jayaram, Radha V.
, p. 146 - 148 (2004)
Selective reduction of α,β-unsaturated carbonyls was studied over CoO-ZrO2 using propan-2-ol as a hydrogen donor and KOH as promoter in a liquid phase reaction. The catalyst used for this synthetically useful transformation showed considerable level of reusability as well as good activity.
A simple and useful synthetic protocol for selective deprotection of tert-butyldimethylsilyl (TBS) ethers
Khan, Abu T.,Ghosh, Subrata,Choudhury, Lokman H.
, p. 2198 - 2204 (2004)
A wide variety of tert-butyldimethylsilyl ethers 1 can be easily cleaved to the corresponding parent hydroxyl compound 2 in the presence of 5 mol % of acetonyltriphenylphosphonium bromide (ATPB) at room temperature. In addition, tert-butyldiphenylsilyl ethers can also be cleaved by using 20 mol % of the same catalyst. Alkyl tert-butyldimethylsilyl ethers can be deprotected to the hydroxyl compounds chemoselectively in the presence of aryl tert- butyldimethylsilyl ethers. Some of the major advantages are mild reaction conditions, no aqueous workup, high efficiency and chemoselectivity and compatibility with other protecting groups; no brominations occur in the aromatic ring under these experimental conditions. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
A NOVEL REDUCING AGENT DERIVED FROM FORMIC ACID AND TWO EQUIVALENTS OF A GRIGNARD REAGENT: CHEMOSELECTIVE REDUCTION OF ALDEHYDES
Babler, James H.,Invergo, Benedict J.
, p. 621 - 622 (1981)
Aldehydes are reduced at a moderate rate by use of a novel reagent obtained by the addition of two molar eqivalents of ethylmagnesium bromide to formic acid in tetrahydrofuran solution.Under similar conditions the reduction of ketones proceeds quite slowly.
Selective deprotection of diphenylmethylsilylethers of allylic and benzylic alcohols
Piva,Amougay,Pete
, p. 219 - 226 (1995)
Selective deprotection of diphenylmethylsilylethers of allylic or benzylic alcohols is achieved by U.V. irradiation in presence of phenanthrene (1eq.) in methylene chloride and methanol. Under these conditions, other ethers containing the t-butyldimethylsilyl or the t-butyldiphenylsilyl group are recovered unmodified.
Ni- and pd-catalyzed synthesis of substituted and functionalized allylic boronates
Zhang, Ping,Roundtree, Ian A.,Morken, James P.
, p. 1416 - 1419 (2012)
Two highly efficient and convenient methods for the synthesis of functionalized and substituted allylic boronates are described. In one procedure, readily available allylic acetates are converted to allylic boronates catalyzed by Ni/PCy3 or Ni/PPh3 complexes with high levels of stereoselectivity and in good yields. Alternatively, the borylation can be accomplished with commercially available Pd catalysts [e.g., Pd 2(dba)3, PdCl2, Pd/C], starting with easily accessed allylic halides.
Chemoselective reduction of α,β-unsaturated carbonyls over novel mesoporous CoHMA molecular sieves under hydrogen transfer conditions
Selvam,Sonavane,Mohapatra,Jayaram
, p. 542 - 544 (2004)
Chemoselective reduction of α,β-unsaturated carbonyls to the corresponding alcohols was achieved by a catalytic transfer hydrogenation (CTH) method using cobalt(II)-substituted hexagonal mesoporous aluminophosphate (CoHMA) molecular sieve catalyst. Further, the catalyst was found to be promising as a heterogeneous catalyst as the yield was practically unchanged after up to six cycles.
FOUR ALIPHATIC ESTERS OF CHAMAEMELUM FUSCATUM ESSENTIAL OILY
Pascual-T., J. De,Caballero, E.,Caballero, C.,Anaya, J.,Gonzalez, M. S.
, p. 1757 - 1760 (1983)
Four new aliphatic esters were isolated from the essential oil of Chamaemelum fuscatum.Three are esters of methacrylicacid with 2-methyl-2E-butenol, 2-hydroxy-2-methyl-3-butenol and 2-hydroxy-2-methyl-3-oxobutanol.The other is neryl isovalerate obtained in addition to known compounds.The structures were determined by spectral measurements and by synthesis.Key Word Index-Chamaemelum fuscatum; Compositae; essential oil; aliphatic esters.
Oxidation of α-hydroxy containing monoterpenes using titanium silicate catalysts: Comments on regioselectivity and the role of acidity
Schofield, Lee J.,Kerton, Owain J.,McMorn, Paul,Bethell, Donald,Ellwood, Simon,Hutchings, Graham J.
, p. 1475 - 1481 (2002)
The regioselective epoxidation of monoterpenes in the liquid phase has been studied using the titanosilicates TS-1 and TiAlβ. A range of oxidants (hydrogen peroxide, tert-butyl hydroperoxide and urea-hydrogen peroxide complex) have been studied in detail. The allylic alcohols linalool and geraniol have been studied alongside the non-allylic alcohol citronellol and the diene dihydromyrcene to help determine the role of the hydroxy group in these reactions. Dihydromyrcene is selectively epoxidised at the more electron rich double bond regardless of the catalyst-oxidant-solvent system used. Geraniol can undergo allylic assisted epoxidation with TS-1-acetone-hydrogen peroxide and TiAlβ-acetonitrile-urea-hydrogen peroxide. With TiAlβ-hydrogen peroxide-methanol, the reaction shows an induction period in the conversion of geraniol which is considered to be characteristic of the autocatalytic removal of titanium from the catalyst framework. Reactions with citronellol show this titanium removal is entirely due to the presence of the allylic alcohol moiety. Finally, epoxidation of linalool and the subsequent in situ conversion of the epoxide to the furano- and pyrano-oxides were studied. The ratio of furano- and pyrano-oxides formed was considered to be due, in part, to the pore geometry and the Br?nsted acidity of the catalyst.
Metal-doped mesoporous ZrO2catalyzed chemoselective synthesis of allylic alcohols from Meerwein-Ponndorf-Verley reduction of α,β-unsaturated aldehydes
Akinnawo, Christianah Aarinola,Bingwa, Ndzondelelo,Meijboom, Reinout
, p. 7878 - 7892 (2021/05/13)
Meerwein-Ponndorf-Verley reduction (MPVr) is a sustainable route for the chemoselective transformation of α,β-unsaturated aldehydes. However, tailoring ZrO2 catalysts for improved surface-active sites and maximum performance in the MPV reaction is still a challenge. Here, we synthesized mesoporous zirconia (ZrO2) and metal-doped zirconia (M_ZrO2, M = Cr, Mn, Fe, and Ni). The incorporation of metal dopants into zirconia's crystal framework alters its physico-chemical properties such as surface area and total acidity-basicity. The prepared catalysts were evaluated in the MPVr using 2-propanol as a hydrogen donor under mild reaction conditions. The catalysts' remarkable reactivity depends mainly on their surface mesostructure's intrinsic properties rather than the specific surface area. Cr_ZrO2, which is stable and sustainable, presented superior activity and 100% selectivity to unsaturated alcohols. The synergistic effect between Cr and Zr species in the binary oxide facilitated the Lewis acidity-induced performance of the Cr_ZrO2 catalyst. Our work presents the first innovative application of a well-designed mesoporous Cr_ZrO2 in the green synthesis of unsaturated alcohols with exceptional reactivity. This journal is
A Bifunctional Copper Catalyst Enables Ester Reduction with H2: Expanding the Reactivity Space of Nucleophilic Copper Hydrides
Kaicharla, Trinadh,Ngoc, Trung Tran,Teichert, Johannes F.,Tzaras, Dimitrios-Ioannis,Zimmermann, Birte M.
supporting information, p. 16865 - 16873 (2021/10/20)
Employing a bifunctional catalyst based on a copper(I)/NHC complex and a guanidine organocatalyst, catalytic ester reductions to alcohols with H2 as terminal reducing agent are facilitated. The approach taken here enables the simultaneous activation of esters through hydrogen bonding and formation of nucleophilic copper(I) hydrides from H2, resulting in a catalytic hydride transfer to esters. The reduction step is further facilitated by a proton shuttle mediated by the guanidinium subunit. This bifunctional approach to ester reductions for the first time shifts the reactivity of generally considered "soft"copper(I) hydrides to previously unreactive "hard"ester electrophiles and paves the way for a replacement of stoichiometric reducing agents by a catalyst and H2.
