We introduce an oxidative Heck reaction for selective complex diene and polyene formation. The reaction proceeds via oxidative Pd(II)/sulfoxide catalysis that retards palladium-hydride isomerizations which previously limited the Heck manifold's capacity for furnishing stereodefined conjugated dienes. Limiting quantities of nonactivated terminal olefins (1 equiv) and slight excesses of vinyl bor...

The protection of conjugated dienes by coordination to the tricarbonyliron fragment offers many potential applications of the resulting complexes to organic synthesis. The preparation of tricarbonyl(h4-1,3-diene)iron complexes is readily achieved by a 1-azabutadiene-catalyzed complexation of the free ligands. An asymmetric catalytic complexation of prochiral cyclohexa-1,3-dienes with pentacarbo...

[reaction: see text] A novel ring opening ring closing metathesis (ROM-RCM) was demonstrated for cyclic conjugated dienes, effecting the excision of a C(2)H(2) unit and a net ring contraction. Applying the ring contraction metathesis, new 14-membered ring macrolide antibiotics were synthesized in a single step from existing 16-membered ring macrolides. This new class of macrolide antibiotics wi...

A new method to rapidly generate pyrrolidines via a SOMO-activated enantioselective (3 + 2) coupling of aldehydes and conjugated olefins has been accomplished. A radical-polar crossover mechanism is proposed wherein olefin addition to a transient enamine radical cation and oxidation of the resulting radical furnish a cationic intermediate which is vulnerable to nucleophilic addition of a tether...

* corresponding author. e-mail: [email protected] Butyl-substituted 1-amino-3-oxocyclohexane-1-carboxylic acid derivatives have been prepared from 5,5-tethered dienes of (2R)-2,5-dihydro-2-isopropyl-3,6-dimethoxypyrazine in stereoselective synthesis. RCM reactions of the diene afforded a heterospirenone which was the substrate for the conjugated addition reaction with lithium dibutylcuprate. Hydrol...

Pd-catalyzed aerobic oxidative coupling of vinylboronic acids and electronically unbiased alkyl olefins provides regioselective access to 1,3-disubstituted conjugated dienes. Catalyst-controlled regioselectivity is achieved by using 2,9-dimethylphenanthroline as a ligand. The observed regioselectivity is opposite to that observed from a traditional (nonoxidative) Heck reaction between a vinyl b...

Conjugated 1,3-dienes are important building blocks in organic and polymer chemistry. Enyne metathesis is a powerful catalytic reaction to access such structural domains. Recent advances and developments in ene-yne cross-metathesis (EYCM) leading to various compounds of interest and their intermediates, that can directly be transformed in tandem procedures, are reviewed in this article. In addi...

A highly selective, radical-mediated (4 + 2) coupling reaction of aldehydes and conjugated olefins has been achieved through asymmetric SOMO-catalysis. A radical-polar crossover mechanism is proposed wherein olefin addition to a transient enamine radical cation and oxidation of the resulting radical furnishes a cation which is vulnerable to nucleophilic addition. A range of aromatic aldehydes a...

The development of novel pharmaceutical compositions, which are effective in the treatment different inflammatory diseases and have a minimum number side effects is very relevant. aim present study was biochemical confirmation anti-inflammatory activity new compositions comprising coxibs caffeine. level conjugated dienes as primary products lipid peroxidation has been evaluated plasma rats at a...