This paper describes a highly chemo- and enantioselective epoxidation of conjugated cis-enynes using readily available glucose-derived ketone 2 as catalyst and Oxone as oxidant to form cis-propargyl epoxides in high ee's. The interaction between the alkyne group of the substrate and the oxazolidinone moiety of the ketone catalyst as ...

Acids, ketones, aldehydes, and alcohols were tested in the laboratory as substrates for hydro-sulphurization under mild conditions. Ketone and aldehyde model compounds (i.e., 2-nonanone, nonanal, cholestan-3-one and phytenal) formed significant amounts of organic sulphur compounds, in which the oxo group was substituted by polysulphide ...

Prochiral heteroaryl ketones containing furan, thiophene, chroman and thiochroman moieties were successfully reduced in the presence of 1 � 10 mol % of spiroaminoborate ester 1 with different borane sources to afford non-racemic alcohols in up to 99% ee. In addition, modest enantioselectivity, around 80% ee, was achieved in the reduction of linear ...

The photodecomposition of four polymer series containing the hexafluoroisopropylidene (6F moiety) was studied. We report herein the photostability of a poly(ether ketone) series when subjected to UV light in air. Replacement of isopropylidene with 6F resu...

The ketones and suffoxides formed in asphalts are the major determinants of viscosity increase on oxidation. Asphalts initially exhibit a high reactivity with oxygen causing a rapid spurt in the formation of both oxidation products and viscosity increase. This spurt is followed by a slower rate of oxidation and hardening. Different oxidation mechanisms appear operative during ...

A substrate-controlled synthesis of (+)-herboxidiene from two lactate-derived chiral ketones is described. Remarkably, most of the carbon backbone was constructed through highly stereoselective titanium-mediated aldol reactions and an Ireland-Claisen rearrangement. Furthermore, an oxa-Michael cyclization and a high-yield Suzuki coupling were used to assemble the pyran ring and ...

The development of a general and mild method for Pd-catalyzed alpha-arylation of a variety of ketones bearing multiple heteroatoms is described. The ligand to metal ratio and the position of the heteroatoms with respect to the carbonyl moiety significantly impact the efficiency of these transformations. In addition, these conditions were successfully ...

[reaction: see text] A new class of thiourea catalysts have been developed which integrate saccharide and primary amine moieties into one small organic molecule. These simple catalysts are shown to be highly enantioselective for direct Michael addition of aromatic ketones to a range of nitroolefins (up to 98% ee). PMID:17288432

Direct hydroxylation of tertiary C-H bonds for construction of 1,3-diaxial diol derivatives was achieved by devising a new detachable dioxirane precursor containing a trifluoromethyl ketone moiety and ethylene tether. Oxone treatment of the ketones led to the corresponding dioxiranes, enabling hydroxy group installment into cyclohexane ...

We report the design of novel, potent cPLA(2)? inhibitors that possess an ?-methyl-2-ketothiazole that acts as a serine-reactive moiety. We describe the optimization of the series for potency and metabolic stability towards ketone reduction. This was achieved by attenuating the reactivity of the ketone using a combination of electronic ...

A model for the spiroiminal moiety of marineosins A and B was prepared starting from methylvalerolactone. Addition of vinylmagnesium bromide, protection of the alcohol, and reaction of the vinyl ketone with a protected pyrrole-2-carbonitrile N-oxide gave an isoxazoline. Hydrogenolysis of the N-O bond with Raney nickel gave a keto imine that cyclized to a ...

A new synthetic method for the removal of the 4, 5-bridged ether moiety of several opioids has been developed. This process offers a faster, simpler synthetic route to obtain the morphinone scaffold in high yields without the need for protection of the ketone moiety.

Unlike the related fenofibrate molecule [Henry, Zhang, Gao & Bruckner (2003). Acta Cryst. E59, o699-o700], fenofibric acid {systematic name: 2-[4-(4-chlorobenzoyl)phenoxy]-2-methylpropanoic acid}, C17H15ClO4, contains a carboxylic acid moiety instead of an ester moiety. This polar moiety plays an important role in the formation of ...

Alkyl substitution ? to the ketone of an allenyl vinyl ketone enhances Nazarov reactivity by inhibiting alternative pathways involving the allene moiety and through electron donation and/or steric hindrance. This substitution pattern also accelerates Nazarov cyclisation by increasing the population of the reactive conformer and by ...

Aryl bromides bearing a potassium trifluoroborate moiety were subjected to lithium-halogen exchange at low temperature using a variety of alkyllithium reagents. A number of different electrophiles were evaluated in their reactions with the aryllithiums produced therein. Under carefully optimized conditions, potassium bromophenyl trifluoroborates afforded good to excellent ...

Conjugate addition of alkylboron compounds (alkyl-9-BBN) to imidazol-2-yl ?,?-unsaturated ketones proceeded in the presence of a catalytic amount (10 mol %) of CuCl, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes), and t-BuOK. The alkylboranes are available through alkene hydroboration, and thus the overall process represents a reductive conjugate addition of alkenes ...

Different diacceptor diazo compounds bearing an ?-PMP-ketone group were found to be effective carbene precursors for the highly stereoselective Rh(2)(S-TCPTTL)(4)-catalyzed cyclopropanation of alkenes (EWG = NO(2), CN, CO(2)Me). The resulting products were readily transformed into a variety of biologically relevant enantiopure molecules, such as cyclopropane ?- and ?-amino ...