2- -1 - 1-alkoxy-1-alkene

Pyridylarenes undergo Cu(II)-catalysed diverse oxidative C-H functionalization reactions. The tolerance of alkene, alkoxy, and aldehyde functionality is a synthetically useful feature of this reaction. A radical-cation pathway (Scheme 4) has been postulated to explain the data from mechanistic studies. A single electron transfer (SET) from the aryl ring to the coordinated Cu(II) leading to the cation-radical intermediate is the rate-limiting step. The lack of reactivity of biphenyl led to the suggestion that the coordination of Cu(II) to the pyridine is necessary for the SET process. The observed ortho selectivity is explained by an intramolecular anion transfer from a nitrogen-bound Cu(I) complex.53... 

The type of monomers suitable for cationic polymerization are those containing an electron-donating substituent such as 1,1-dialkyl, alkene, alkoxy, and phenyl that stabilize the propagating cationic centers. Successftil industrial examples include polyisobutylene and its copolymers with dienes such as butyl mbber. In ionic polymerization, initiator is conventionally called a catalyst. However, by definition, catalyst and initiator are two different types of reagents. Catalyst takes part in reactions but can be removed from the final product if necessary. On the other side, initiator molecules or their fragments become a part of the produced chains after polymerization. In cationic polymerization, a single catalyst is not sufficient and a cocatalyst is required. Typical catalysts are Lewis acids such as BF3, AICI3, and TiCU that must be used with a protonic cocatalyst such as H2O and methanol ... 

As a unique reaction of Pd(II), the oxidative carbonylation of alkenes is possible with Pd(ll) salts. Oxidative carbonylation is mechanistically different from the hydrocarboxylation of alkenes catalyzed by Pd(0), which is treated in Chapter 4, Section 7.1. The oxidative carbonylation in alcohol can be understood in the following way. The reaction starts by the formation of the alkoxy-carbonylpalladium 218. Carbopalladation of alkene (alkene insertion) with 218 gives 219. Then elimination of /3-hydrogen of this intermediate 219 proceeds to... 

The first report of oxidative carbonylation is the reaction of alkenes with CO in benzene in the presence of PdCh to afford the /3-chloroacyl chloride 224[12,206]. The oxidative carbonylation of alkene in alcohol gives the q, f3-unsaturated ester 225 and /3-alkoxy ester 226 by monocarbonylation, and succinate 111 by dicarbonylation depending on the reaction conditions[207-209]. The scope of the reaction has been studied[210]. Succinate formation takes... 

The TT-allylpalladium complexes formed from conjugated dienes are reactive and react further with a nucleophile to give the 1,4-difunctionalized products 340. Based on this reaction, various nucleophiles are introduced into conjugated dienes to form 1,4-difunctionalized 2-alkenes. Acetoxy, alkoxy, halo, and... 

In spite of the ene ending to its name polyethylene is much more closely related to alkanes than to alkenes It is simply a long chain of CH2 groups bearing at its ends an alkoxy group (from the initiator) or a carbon-carbon double bond... 

Nitronates derived from primary nitroalkanes can be regarded as a synthetic equivalent of nitrile oxides since the elimination of an alcohol molecule from nitronates adds one higher oxidation level leading to nitrile oxides. This direct / -elimination of nitronates is known to be facilitated in the presence of a Lewis acid or a base catalyst [66, 72, 73]. On the other hand, cycloaddition reactions of nitronates to alkene dipolarophiles produce N-alkoxy-substituted isoxazolidines as cycloadducts. Under acid-catalyzed conditions, these isoxazolidines can be transformed into 2-isoxazolines through a ready / -elimination, and 2-isoxazolines correspond to the cycloadducts of nitrile oxide cycloadditions to alkenes [74]. 

E)-alkene dipeptide isostere 48, 51, 63 alkenylepoxide 42 alkoxy carbonyl protecting group 32 P-alkoxy-a-amino esters... 

The ability of Fischer carbene complexes to transfer their carbene ligand to an electron-deficient olefin was discovered by Fischer and Dotz in 1970 [5]. Further studies have demonstrated the generality of this thermal process, which occurs between (alkyl)-, (aryl)-, and (alkenyl)(alkoxy)carbene complexes and different electron-withdrawing substituted alkenes [6] (Scheme 1). For certain substrates, a common side reaction in these processes is the insertion of the carbene ligand into an olefinic C-H bond [6, 7]. In addition, it has been ob-... 

Non-heteroatom-stabilised Fischer carbene complexes also react with alkenes to give mixtures of olefin metathesis products and cyclopropane derivatives which are frequently the minor reaction products [19]. Furthermore, non-heteroatom-stabilised vinylcarbene complexes, generated in situ by reaction of an alkoxy- or aminocarbene complex with an alkyne, are able to react with different types of alkenes in an intramolecular or intermolecular process to produce bicyclic compounds containing a cyclopropane ring [20]. 

Alkoxy (R0 ) radicals react at near diffusion controlled rates with trialkyl phosphites to give phosphoranyl radicals [ROP(OR )3] that typically undergo very fast -scission to generate alkyl radicals (R ) and phosphates [OP(OR )3]. In a mechanistic study, trimethyl phosphite, P(OMe)3, has been used as an efficient and selective trap in oxiranylcarbinyl radical systems formed from haloepoxides under thermal AIBN/n-Bu3SnH conditions at about 80 °C (Scheme 27) [64]. The formation of alkenes resulting from the capture of allyloxy radicals by P(OMe)3 fulfils a prior prediction that, under conditions close to kinetic control, products of C-0 cleavage (path a. Scheme 27), not just those of C-C cleavage (path b. Scheme 27) may result. 

See Sodamide Aryl halide, l-Alkoxy-l-(trimethylsilyloxy)alkenes... 

Aryl halide, l-Alkoxy-l-(trimethylsilyloxy)alkenes Ferguson, J. R. et al., Chem. Brit., 1997, 33(6), 21... 

Alkyl and silyl nitronates are, in principle, /V-alkoxy and /V-silyloxynitrones, and they can react with alkenes in 1,3-dipolar cycloadditions to form /V-alkoxy- or /V-silyloxyisoxaz.olidine (see Scheme 8.25). The alkoxy and silyloxy groups can be eliminated from the adduct on heating or by acid treatment to form 2-isoxazolines. It should be noticed that isoxazolines are also obtained by the reaction of nitrile oxides with alkenes thus, nitronates can be considered as synthetic equivalents of nitrile oxides. Since the pioneering work by Torssell et al. on the development of silyl nitronates, this type of reaction has become a useful synthetic tool. Recent development for generation of cyclic nitronates by hetero Diels-Alder reactions of nitroalkenes is discussed in Section 8.3. 

Some remarks concerning the scope of the cobalt chelate catalysts 207 seem appropriate. Terminal double bonds in conjugation with vinyl, aryl and alkoxy-carbonyl groups are cyclopropanated selectively. No such reaction occurs with alkyl-substituted and cyclic olefins, cyclic and sterically hindered acyclic 1,3-dienes, vinyl ethers, allenes and phenylacetylene95). The cyclopropanation of electron-poor alkenes such as acrylonitrile and ethyl acrylate (optical yield in the presence of 207a r 33%) with ethyl diazoacetate deserve notice, as these components usually... 

Individual aspects of nitrile oxide cycloaddition reactions were the subjects of some reviews (161 — 164). These aspects are as follows preparation of 5-hetero-substituted 4-methylene-4,5-dihydroisoxazoles by nitrile oxide cycloadditions to properly chosen dipolarophiles and reactivity of these isoxazolines (161), 1,3-dipolar cycloaddition reactions of isothiazol-3(2//)-one 1,1-dioxides, 3-alkoxy- and 3-(dialkylamino)isothiazole 1,1-dioxides with nitrile oxides (162), preparation of 4,5-dihydroisoxazoles via cycloaddition reactions of nitrile oxides with alkenes and subsequent conversion to a, 3-unsaturated ketones (163), and [2 + 3] cycloaddition reactions of nitroalkenes with aromatic nitrile oxides (164). 

Very recently, Murakami has published an Rh(i)-catalyzed cyclization of 1,6-enynes triggered by addition of arylboronic acids (Scheme 74).281 Initial carborhodation of the alkyne moiety is followed by insertion into the alkene moiety. /3-Alkoxy elimination provides the final product 289 in good yield and regenerates the catalyst species. 

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