Carbene catalysed redox activation of α,β-unsaturated aldehydes is applied for generation of α,β-unsaturated acyl azoliums which undergo cyclopropanation upon reaction with a sulfur ylide and an alcohol to give the corresponding cyclopropanecarboxylic acid esters. With chiral carbenes good to excellent diastereo and enantioselectivities are obtained.

Highly efficient DABCO-catalyzed [4 + 2] cycloaddition of β,γ-unsaturated α-ketophosphonates or β,γ-unsaturated α-ketoesters with allenic esters gives the corresponding highly functionalized tetrahydropyran and dihydropyran derivatives in good to excellent yields and moderate to good regioselectivities under mild conditions.

Bridgehead bicyclic unsaturated enamines were prepared by a tandem rhodium-catalyzed C-H bondactivation/alkenylation/electrocyclization of alkyne-tethered unsaturated imines. These strained bicyclic enamines exhibitunique reactivity: for example, they give N-Alkylated products upon treatment with alkylating reagents and undergo doublebond isomerization to alleviate ring strain upon ...

An efficient and high-yield procedure to prepare methyl N-benzoylamino-3-arylacrylates from unsaturated (Z)-2-aryl-4-arylidene-5-(4H)-oxazolones and Hg(OAc)2 in methanol is described herein. The observed reactivity of mercury(II) acetate here is different to its usual metallating behaviour, since it cleaves the unsaturated oxazolone ring without change of stereochemistry.

Ir-ReOx/SiO2 acted as a highly active and selective heterogeneous catalyst for the hydrogenation of unsaturated aldehydes to unsaturated alcohols in water at low H2 pressure (0.8 MPa) and low temperature (303 K). The catalysis is derived from the synergy between Ir metal and ReOx.

Five new bulky moiety-modified analogues of the sandalwood odorant Polysantol have been synthesized by aldol condensation of appropriate aldehydes with butanone, deconjugative alpha-methylation of the resulting alpha,beta-unsaturated ketones, and reduction of the corresponding beta,gamma-unsaturated ketones. The final compounds were evaluated organoleptically and one of them seemed to be of spe...

The binding of estradiol to uterine cytosoluble receptors from 24-day-old rats was reduced or potentiated by unsaturated fatty acids (NEFAs), depending on the concentrations of estradiol and unsaturated NEFAs. At estradiol concentrations of up to 1.5 x 10(-8) M, unsaturated NEFAs inhibited estradiol binding to the 8 S cytosol receptor. This inhibition was dose-dependent (10-70%, p less than 0.0...

The mechanism by which dietary unsaturated fatty acids lower low density lipoprotein (LDL) cholesterol is unknown. Unsaturated fatty acids incorporated into the cell membrane can increase membrane fluidity and, as a result, dramatically alter membrane-dependent cell functions. Therefore, we examined the effect of long-term dietary consumption of corn oil and coconut oil with and without cholest...

Cholesterol balance studies were carried out in 11 patients with various types of hyperlipoproteinemia to determine the mechanism by which unsaturated fats lower plasma cholesterol. Unsaturated fats produced no increase in fecal endogenous neutral steroids in 10 of 11 patients and no decrease in absorption of exogenous cholesterol in 5 patients who received cholesterol in the diet. In 8 of 11 p...

An easy to operate method of catalytic hydroboration of unsaturated compounds has been developed with wide substrate scope. Reactions of various aldimines, ketimines, α,β-unsaturated carbonyl compounds, and alkynes were successfully executed with bis(pinacolato)diboron and N-heterocyclic carbenes in methanol without requiring a transition metal or inert atmosphere.