51473-70-2Relevant academic research and scientific papers
Transfer hydrogenation of aromatic and linear aldehydes catalyzed using Cp*Ir(pyridinesulfonamide)Cl complexes under base-free conditions
Townsend, Tanya M.,Kirby, Christopher,Ruff, Andrew,O'Connor, Abby R.
, p. 7 - 13 (2017/05/19)
Cp*Ir(pyridinesulfonamide)Cl (Cp*?=?pentamethylcyclopentadienyl) precatalysts 1–7 are active for the transfer hydrogenation of aryl, alkyl, and heterocyclic aldehydes. Catalysis is conducted under base-free conditions in air without dried or degassed substrates and solvents. These reductions occur rapidly in moderate to high conversion (39–100%). Benzaldehyde derivatives are reduced to alcohols within 30?min?at 85?°C using 1?mol% iridium precatalyst; reduction also occurs at lower temperatures and loadings (60?°C, 0.50?mol% precatalyst). Benzaldehyde derivatives that possess electron-rich and electron-poor substituents in the para position, including base-sensitive 4-hydroxybenzaldehyde, are readily reduced. Aryl aldehydes containing electron-poor groups are reduced faster than substrates possessing electron-rich moieties. Reduction of the positional isomers of methoxybenzaldehyde and isopropylbenzaldehyde shows highest reduction for the ortho isomer, followed by the meta isomer. Heterocyclic substrates, including biomass derived 5-hydroxymethylfurfural and 2-furfural, were reduced selectively to the alcohol. Decyl aldehyde was reduced to the linear alcohol; importantly self-condensation was not observed. Competition studies demonstrated selective reduction of aldehydes over ketones and a mercury poisoning experiment supports a homogeneous catalyzed pathway.
Useful catalytic enantioselective cationic double annulation reactions initiated at an internal π-bond: Method and applications
Surendra, Karavadhi,Rajendar, Goreti,Corey
supporting information, p. 642 - 645 (2014/02/14)
The 1:1 complex of o,o'-dichloro-R-BINOL and SbCl5 initiates the enantioselective cationic polycyclization of polyunsaturated substrates at a predictable π-bond which may be either terminal or, as shown herein, internal. The extension of this powerful construction to internal π-bonds expands the scope of this method and opens up very short pathways to numerous chiral polycyclic molecules, including natural products and their analogues. Especially simple synthetic routes are disclosed that provide access to dysideapalaunic acid, dehydroabietic acid, and epipodocarpic acid and illustrate the value of this enantioselective approach.
Oxidative degradation of fragrant aldehydes. Autoxidation by molecular oxygen
Marteau,Ruyffelaere,Aubry,Penverne,Favier,Nardello-Rataj
, p. 2268 - 2275 (2013/04/10)
The oxidative degradation of fragrant aldehydes by molecular oxygen has been investigated. The oxygen consumption was monitored and the bond dissociation energy (BDE) of the aldehyde C(O)-H bond were calculated by DFT method. The oxidation products were identified by GC/MS. The different pathways accounting for the oxidative degradation are discussed. The main product is the acid, beside the formate ester. Both oxidation products result from the Baeyer-Villiger reaction involving a peracid R(CO)OOH whereas minor products arise from the hydroperoxide ROOH intermediate derived either from the acyl peroxy radical, R(CO)OO or from the decarboxylation of the peracid RC(O)OOH.
Enantioselective copper-catalyzed conjugate addition of trimethylaluminium to β,γ-unsaturated α-ketoesters
Gremaud, Ludovic,Alexakis, Alexandre
, p. 794 - 797 (2012/03/09)
Not a cop out: The copper-catalyzed asymmetric conjugate addition of organometallic reagents to Michael acceptors is an important methodology for forming a C-C bond in an enantioselective manner. Such an addition of Me 3Al to β,γ-unsaturated α-
Catalytic diastereoselective polycyclization of homo(polyprenyl)arene analogues bearing terminal siloxyvinyl groups
Uyanik, Muhammet,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 5649 - 5652 (2007/10/03)
Highly diastereoselective polycyclization of homo(polyprenyl)arene analogues bearing terminal siloxyvinyl groups was catalyzed by tin(IV) chloride (10 mol %). The cyclizations of tert-butyldiphenylsilyl and triisopropylsilyl polyenol ethers gave 4α(equatorial)- and 4β(axial)-siloxypolycycles as major isomers, respectively. The strong nucleophilicity of pro-C(9), a (6E) geometry, and a bulky silyl group effectively favored the 4α-preference, whereas the weak nucleophilicity of pro-C(9), a (6Z)-geometry, and less steric hindrance of a silyl group favored the 4β-preference.
