Diene-allenes

FIGURE 10 7 Bonding and geometry in 1 2 propa diene (allene) The green and yellow colors are meant to differentiate the orbitals and do not indicate their phases... 

Osakada, K. and Takeuchi, D. Coordination Polymerization of Dienes, Allenes, and Methyl-enecydoalkanes. Vol. 171, pp. 137-194. 

Alkynes, alkenes, dienes, allenes, isonitriles, carbonyl compounds, etc. 

Angularly substituted bicyclo[4.3.0] systems can be synthesized efficiently through a rhodium-catalyzed intramolecular [4 + 2] diene-allene cycloaddition protocol (Scheme 16.74) [80]. 

Abstract The basic principles of the oxidative carbonylation reaction together with its synthetic applications are reviewed. In the first section, an overview of oxidative carbonylation is presented, and the general mechanisms followed by different substrates (alkenes, dienes, allenes, alkynes, ketones, ketenes, aromatic hydrocarbons, aliphatic hydrocarbons, alcohols, phenols, amines) leading to a variety of carbonyl compounds are discussed. The second section is focused on processes catalyzed by Pdl2-based systems, and on their ability to promote different kind of oxidative carbonylations under mild conditions to afford important carbonyl derivatives with high selectivity and efficiency. In particular, the recent developments towards the one-step synthesis of new heterocyclic derivatives are described. 

Scheme 11.7 Intramolecular rhodium-catalyzed [4-r2]-diene allene carbocyclization.

Recent advances in the rhodium-catalyzed [4-1-2] reactions have led to the development of the first highly regioselective intermolecular cyclization, providing access to new classes of carbocycles with both activated and unactivated substrates. The chemo- and stereoselective carbocyclizations of tethered diene-allene derivatives afford new classes of 5,6- and 6,6-bicyclic systems. Additionally, examination of a wide range of factors that influence both diastereo- and enantioselectivity has provided a significant advance in the understanding of catalyst requirements across these systems. 

Most monomers contain only one polymerizable group. There are some monomers with two polymerizable groups per molecule. Polymerization of such monomers can lead to more than one polymer structure. The polymerization of 1,3-dienes, of large industrial importance, is discussed in Sec. 8-6. 1-Substituted-l,2-dienes (allenes) undergo polymerization through both the substituted and unsubstituted double bonds... 

Analogous intermolecular processes involving various unsaturated substrates such as non-conjugated dienes, allenes, methylenecydopropanes as well as addi-... 

When 1,2-diene (allene) derivative 60 is treated with aryl halide in the presence of Pd(0), the aryl group is introduced at the central carbon by the insertion of one of the allenic double bonds to form the 7i-allylpalladium intermediate 61, which is attacked by an amine to give the allylic amine 62. A good ligand for the reaction is dppe [30]. 

Dienes (allenes) are also used for heteroannulation with 68 and 69. The eight-membered nitrogen heterocycle 78 is constructed by the reaction of 1,2-undecadiene (77) with o-(3-aminopropyl)iodobenzene (76) [34]. The lactones are prepared by trapping the 7i-allyl intermediates with carboxylic acids as an oxygen nucleophile. The unsaturted lactone 81 is prepared by the reaction of /1-bromo-v,/ -unsaturated carboxylic acid 79 with the allene 80 [35]. In the carboannulation of 82 with 1,4-cyclohexadiene (83), the 1,3-diene 85 is generated by / -elimination of 84, and the addition of H-PdX forms the 7i-allylpalladium 86, which attacks the malonate to give 87 [36],... 

Ni- and Rh-catalyzed intramolecular [4+2] cycloadditions of the diene-allene 65 using tri(o-phenylphenyl) phosphite gave the different products 66 and 67 [21],... 

Metal complexes enable one to employ molecules that are thermally unreactive toward cycloadditions by taking advantage of their ability to be activated through complexation. Most of the molecules activated by transition-metal complexes involve C-C unsaturated bonds such as alkynes, alkenes, 1,3-dienes, allenes, and cyclopropanes. In contrast, carbonyl functionalities such as aldehydes, ketones, esters, and imines seldom participate in transition-metal-catalyzed carbonylative cycloaddition reactions. Recently, such a transformation was reported via the use of ruthenium complexes. 

Keywords Coordination polymerization Diene Allene Methylenecyclopropane Copolymerization... 

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