gem-Difluoro-1,7-enyne amides are suitable building blocks for the synthesis of difluorodihydropyridinones via a ring-closing metathesis reaction, and of 4,4-difluoro-3-oxoisoquinolines through a ring-closing metathesis-enyne metathesis tandem reaction. These products, in turn, undergo a Diels-Alder reaction to yield heterotricyclic systems in moderate to good yields.

In our searching program for novel sorbicillin related compounds, three novel compounds, spirosorbicillinols A (1), B (2), and C (3), were isolated from the fermentation broth of the USF-4860 strain isolated from a soil sample. The planar structures of compounds 1-3 were determined from spectroscopic evidence and degradation reaction, and that of 1 was the same as that of 2. The relative stereo...

Phosphorothioate diester oligonucleotides proved to be fully compatible with maleimides in the context of two different conjugation reactions: (a) reaction of (5')diene-[phosphorothioate oligonucleotides] with maleimido-containing compounds to afford the Diels-Alder cycloadduct; (b) conjugation of (5')maleimido-[phosphorothioate oligonucleotides] with thiol-containing compounds. No evidence of ...

A one-pot tandem process involving an Overman rearrangement, ring closing enyne metathesis and a hydrogen bonding directed Diels-Alder reaction has been developed for the efficient diastereoselective synthesis of functionalised amino substituted tetralin and indene ring systems.

Dimeric forms of norbornadiene and benzonorbornadiene were synthesized starting with known monobromide derivatives. The Diels-Alder cycloaddition reaction of dimers with TCNE and PTAD was investigated and new norbornenoid polycyclics were obtained. All compounds were characterized properly using NMR spectroscopy.

In this update on the Diels-Alder reaction we would like to present an overview on how this very important reaction has progressed in the last decade, since the last spate of monographs and reviews appeared in the literature, and which deal with the reaction in the overall sense. Initially we present the Diels-Alder reaction in a generalised form, much as discovered over seventy years ago, so t...

Pyridine-C-nucleosides, „Inverse“ [4+2] Cycloadditions, 1,2,4-Triazine-C-nucleosides, 2,,3’-Dideoxy-/?-D-ribofuranosyl-pyridines The anomeric imido esters 5 and 6, appropriate precursors for C-nucleoside synthesis, were prepared and utilized as heterodienophiles in a Diels-Alder reaction with inverse electron demand to yield the novel, protected 1.2.4-triazine C-nucleosides 8 and 9. They could ...

A one-pot procedure is described for using alpha,beta-unsaturated aldehydes as olefin equivalents in the Diels-Alder reaction. The method combines the normal electron demand cycloaddition with aldehyde dienophiles and the rhodium-catalyzed decarbonylation of aldehydes to afford cyclohexenes with no electron-withdrawing substituents. In this way, the aldehyde group serves as a traceless control ...

The anion-radical coupling of structurally diverse series of aromatic compounds possessing biaryl linkages led to seven fused, polycyclic heterocycles in reasonable yields. The yield of the key step (K, toluene, O2) depends on both electronic and steric factors. The whole strategy consists of just two steps starting from an unsubstituted imidazo[1,2-a]pyridine, giving target compounds in an ove...

reaction of 2-dimethylphosphono-1,3-benzodithiole 3a with conjugated 1,4-diketones for the preparation of 2,2'-bis(I,3dithiole) donors.[41 We have now used the Wittig-Horner reaction of 3 b, which was synthesized by a similar method as that for 3a,15] to prepare 1. In this case, a cyclopentadiene adduct ofp-benzoquinone 4 was used as a diketone and after introduction of the 1,3-dithiole rings t...