Highly pH-Dependent Chemoselective Transfer Hydrogenation of α,β-Unsaturated Aldehydes in Water
作者:Nianhua Luo、Jianhua Liao、Lu Ouyang、Huiling Wen、Jitian Liu、Weiping Tang、Renshi Luo
DOI:10.1021/acs.organomet.9b00353
日期:2019.8.12
electron-poor substituents on the aryl group of α,β-unsaturated aldehydes can be tolerated, affording the corresponding products in excellent yields with high TOF values. High selectivity and yields were also observed for α,β-unsaturated aldehydes with aliphatic substituents. Our mechanistic investigations indicate that the pH value is critical to the chemoselectivity.
Nickel-Catalyzed Asymmetric Kumada Cross-Coupling of Symmetric Cyclic Sulfates
作者:Meredith S. Eno、Alexander Lu、James P. Morken
DOI:10.1021/jacs.6b03384
日期:2016.6.29
Nickel-catalyzed enantioselective cross-couplings between symmetric cyclic sulfates and aromatic Grignard reagents are described. These reactions are effective with a broad range of substituted cyclic sulfates and deliver products with asymmetric tertiary carbon centers. Mechanistic experiments point to a stereoinvertive SN2-like oxidative addition of a nickel complex to the electrophilic substrate
Highly enantioselective hydrogenation of a variety of 2-substituted-2-alkenols has been achieved using a ChenPhosâRh complex as catalyst, giving â¥99% ee for most substrates. Optically active antifungal agent amorolfine was first synthesised using hydrogenation as the key step.
Synthesis of 1,3,4,5-Tetrahydro-2-benzoxepin Derivatives as Conformationally Restricted Analogues of cyclamenaldehyde-type compounds and as intermediates for highly odour-active homologues
作者:Georges Skouroumounis、B�at Winter
DOI:10.1002/hlca.19960790418
日期:1996.6.26
Nine 1,3,4,5-tetrahydro-2-benzoxepinderivatives have been prepared as mimics of the folded (gauche) conformation of cyclamenaldehyde (1) and related compounds, but none of them showed the typical lily-of-the valley (muguet) odour activity. However, conversion of these substances to previously unknown analogues of 1 having a Me substituent on the aromatic ring in an ortho position to the side chain
Compounds of formula (I): or stereoisomers or pharmaceutically acceptable salts thereof, wherein W, R
1
, R
2
and R
3
have the meanings as indicated in the specification, are useful for treating conditions mediated by activation of the adenosine A
2A
receptor, especially inflammatory or obstructive airways diseases. Pharmaceutical compositions that contain the compounds and a process for preparing the compounds are also described.