The first total synthesis of garsubellin A, a neurotrophic compound with potent choline acetyltransferase-inducing activity, is described. Keys for success were (1) stereoselective intermolecular aldol reaction at the C-4 position with acetaldehyde, (2) stereoelective Claisen rearrangement to introduce an allyl group to the most sterically crowded position at C-6, (3) ring-closing metathesis to...

The relative configuration of the title compound, C(11)H(18)O(3), which was synthesized using a catalytic asymmetric Gosteli-Claisen rearrangement, a diastereoselective reduction with K-Selectride and an Evans aldol addition, was corroborated by single-crystal X-ray diffraction analysis. The five-membered ring has an envelope conformation with a dihedral angle of 29.46 (16)° between the coplana...

Synthesis of novel pyrazole-fused heterocycles, i.e., dihydro-1Hor 2H-oxepino[3,2c]pyrazoles (6 or 7) from 4-allyloxy-1H-pyrazoles (1) via combination of Claisen rearrangement and ring-closing metathesis (RCM) has been achieved. A suitable catalyst for the RCM of 5-allyl-4allyloxy-1H-pyrazoles (4) was proved to be the Grubbs second generation catalyst (Grubbs2nd) to give the predicted RCM produ...

Background α-Methylene cycloalkanones are considered of interest because of their biological activity. Herein, in this paper the synthesis of (±) HomoSarkomycine Esters was described and characterized. Methods Using Bylis-Hillman adducts, triethlorthoacetate and propanoic acid, (±) HomoSarkomycine Esters could be synthesized by smoothly Johnson-Claisen rearrangement. Results A small library...

The napyradiomycins are an intriguing family of halogenated natural products with activity against several tumor cell lines as well as some of the worst bacterial strains known to humanity, including methicillin-resistant Staphylococcus aureas and vancomycin-resistant strains of Enterococcus faecium. This communication delineates the first asymmetric total synthesis of (-)-napyradiomycin A1 by ...

Thermal decomposition of a series of diazodicarbonyl compounds in the presence of α,β-unsaturated δ-amino esters and sodium hydride gives rise to a variety of nitrogenous heterocycles. The direction of these processes is highly dependent on the structure of the initial reagents giving rise to the formation of multi-functionalized 2-oxopiperidines, 5,6-dihydropyridin-2(1H)-ones or tetrahydroisoq...

Standard free energies (DeltaGN degree) for formation of near attack conformers, those ground state conformers that can convert directly to the transition state, were calculated for the Claisen rearrangement of chorismate to prephenate in six different environments: water, wild-type enzymes from Bacillus subtilis and Escherichia coli, their Arg90Cit and Glu52Ala mutants, and the 1F7 catalytic a...