Ring-Opening Reactions Of Methylenecyclopropanes Research Articles

Palladium‐Catalyzed Cross‐Coupling Reactions of 2‐Iodo‐4‐(phenylchalcogenyl)‐1‐butenes.

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Palladium-Catalyzed Cross-Coupling Reactions of 2-Iodo-4-(phenylchalcogenyl)-1-butenes

[reaction: see text] 2-Iodo-4-(phenylchalcogenyl)-1-butenes 2 or 3, which are derived from the ring-opening reaction of methylenecyclopropanes (MCPs) 1 by iodine, can be applied to some palladium-catalyzed cross-coupling reactions such as the Sonogashira, Heck, Kumada, Suzuki, and Negishi reactions under mild conditions to give the corresponding coupling products in good yields. These reactions proceeded smoothly at room temperature (20 degrees C) in most cases without any phosphine ligand and additive. The phenylchalcogenyl group plays an important role in the reactions and a plausible reaction mechanism has been proposed.

Facile Synthesis of Cross‐Conjugated gem‐Disubstituted Trienes via Palladium‐Catalyzed Cross‐Coupling Protocol of 1,1‐Disubstituted 2,4‐Diiodo‐but‐1‐ene with Alkenes.

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Ring-opening reaction of methylenecyclopropanes with LiCl, LiBr or NaI in acetic acid

The methylenecyclopropanes 1 react with LiCl, LiBr or NaI at 80 °C to give the corresponding gem-disubstituted homoallylic halides 2 in good to excellent yields in acetic acid. In some cases, the ring-opening reaction can be completed within 5 min to give the corresponding gem-disubstituted homoallylic halides in high yields.

Ring-opening reactions of methylenecyclopropanes with diphenyl diselenide upon heating; formation of 3-phenylselenyl-2,5-dihydrofuran derivatives

The reactions of methylenecyclopropanes with diphenyl diselenide give ring-opened products in good yields at 150 [degree]C under nitrogen atmosphere for 3 h; the products can further undergo oxidative cyclization with hydrogen peroxide to furnish 3-phenylselenyl-2,5-dihydrofurans in moderate yields (three steps) at room temperature in CH(2)Cl(2) for 5 h; a plausible reaction mechanism has been proposed.

Facile Synthesis of Cross-Conjugatedgem-Disubstituted Trienes via ­Palladium-Catalyzed Cross-Coupling Protocol of 1,1-Disubstituted 2,4-Diiodo-But-1-ene With Alkenes

Cross-conjugated coupling products described in the title are obtained in moderate to high yields by the reactions of the corresponding 1,1-disubstituted 2,4-diiodo-but-1-enes, which are derived from the ring-opening reaction of methylenecyclopropanes with iodine, with substituted alkenes in the presence of palladium(II) catalyst under simple Heck-type reaction conditions.

Heptadecafluorooctanesulfonic acid catalyzed ring opening reactions of methylenecyclopropanes with aromatic amines, sulfonamides and alcohols in supercritical carbon dioxide

The ring opening reactions of methylenecyclopropanes (MCPs) with ArNH2, RSO2NH2 and alcohols can be carried out in scCO2 in the presence of heptadecafluorooctanesulfonic acid which offer a way to synthesize homoallylic amines, sulfonamides and ethers in environmentally benign conditions.

A novel ring-opening reaction of methylenecyclopropanes with aromatic amines catalyzed by Lewis acids

Methylenecyclopropanes (MCPs) can react with aromatic amines to give the corresponding homoallylic amines in good to high yields in the presence of Lewis acids. The substituents on the benzene ring of the MCPs or the aromatic amines can affect significantly the reaction rate.

Role of orbital symmetry in transition metal promoted ring opening reactions of methylenecyclopropanes and cyclobutenes

Transition metals catalyse a variety of organic reactions, of which the ring opening of strained ring organic molecules generated a lot of interest. Theoreticians predicted a metal orbital catalysed pathway, which involved concerted bond breaking and bond forming. On the other hand experimentalists were able to show that the reaction was not proceeding through a concerted pathway by intercepting the intermediates involved. There remained, however, two ring systems methylenecyclopropanes and cyclobutenes—whose reactions with metal complexes seemed to be of a concerted nature. An analysis of the reactions of different metal complexes with these ring systems and the theoretical predictions provide a rationale for understanding these reactions.