Alkenylation and Amination

C-H activation of ethyl acrylate was also considered and found to have a higher barrier of 25.1 kcal mol .  

This chapter has surveyed the contribution of computational chemistry in understanding the mechanisms of heteroatom-assisted C-H bond activations at Pd as well as Ru, Rh, and Ir metal centers. The underlying basis of these processes is now well understood with the combination of an electron-deficient metal center and a chelating base providing a powerful means to cleave C-H bonds, especially when a directing group is employed to facilitate this process. Intermolecular C-H activation of (hetero)arenes is now well documented, particularly at Pd(II) where the 

We thank Prof Dai Davies (University of Leicester) and his group for many fruitful discussions and the EPSRC for financial support through awards EP/J002712/1 (KJTC) andEP/J021911/l (CLM). 

Aullon, G, Chat, R-, Favier, I., Font-Bardia, M., Gomez, M., Granell, 

Liu and coworkers reported a base-modulated regioselective Pd-catalyzed intramolecular aerobic oxidative amination of alkenes for five- or seven-memberedring products by varying the reaction conditions [12]. 

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The rather unreactive chlorine of vinyl chloride can be displaced with nucleophiles by the catalytic action of PdCb. The conversion of vinyl chloride to vinyl acetate (797) has been studied extensively from an industrial standpoint[665 671]. DMF is a good solvent. 1,2-Diacetoxyethylene (798) is obtained from dichloroethylene[672]. The exchange reaction suffers steric hindrance. The alkenyl chloride 799 is displaced with an acetoxy group whereas 800 and 801 cannot be displaccd[673,674]. Similarly, exchange reactions of vinyl chloride with alcohols and amines have been carried out[668]. 

Iminium ions are reactive electrophiles toward both alkenyl and allylic silanes. Useful techniques for closing nitrogen-containing rings are based on in situ generation of iminium ions from amines and formaldehyde.121... 

The action of chloroamine and bromoamine on organometallic reagents has been reviewed102 and a comprehensive review of electrophilic aminations of carbanions has appeared103. Alkyl, alkenyl and aryllithium compounds are converted into tertiary amines 84 by reaction with the mesityl compounds 83 (R2 = Me or Et Ar = 2,4, 6-MesCeHj)104. 

Some substituted guanidines have been obtained [457] by reaction of amines with the disulphide H2N(HN )C S S C( NH)NH2. Papers on the structure and p/fa s [458], and the synthesis [458, 459] of acylguanidines have been published. Reaction of guanidine with alkyl-, alkenyl-, and benzyl-halides, followed by distillation under basic conditions, is reported to give useful yields of amines [460]. A novel electrophilic substitution of benzene to give A -methyl-A -phenyl-guanidine amongst other products has been published [461 ]. 

Aromatic carboxylic acids, a,/f-unsaturated carboxylic acids, their esters, amides, aldehydes and ketones, are prepared by the carbonylation of aryl halides and alkenyl halides. Pd, Rh, Fe, Ni and Co catalysts are used under different conditions. Among them, the Pd-catalysed carbonylations proceed conveniently under mild conditions in the presence of bases such as K2CO3 and Et3N. The extremely high toxicity of Ni(CO)4 almost prohibits the use of Ni catalysts in laboratories. The Pd-catalysed carbonylations are summarized in Scheme 3.9 [215], The reaction is explained by the oxidative addition of halides, and insertion of CO to form acylpalladium halides 440. Acids, esters, and amides are formed by the nucleophilic attack of water, alcohols and amines to 440. Transmetallation with hydrides and reductive elimination afford aldehydes 441. Ketones 442 are produced by transmetallation with alkylmetal reagents and reductive elimination. 

Fig. 12.13 Reductive amination conditions yielding an unexpected IV-alkenyl and the desired iV-alkyl homospermine analogues...

Electrophilic substitutions of alkenyl-, aryl-, and alkynylsilanes with heteroatom-stabilized cationic carbon species generated by the action of a Lewis or Brpnsted acid (acyl cation, oxocarbenium ion, etc.) provide powerful methods for carbon-carbon bond formation. Particularly, intramolecular reactions of alkenylsilanes with oxocarbenium and iminium ions are very valuable for stereoselective construction of cyclic ether and amine units.21-23 For example, the BFj OEt -promoted reaction of (E)- and (Z)-alkenylsilanes bearing an acetal moiety in the alkenyl ligand gives 2,6-disubstituted dihydropyrans in a stereospecific manner (Scheme l).23 Arylsilanes also can be utilized for a similar cyclization.24... 

Tetrahydrocarbazoles and related fused systems have been accessed by a route relying on palladium-catalyzed tandem formation of alkenyl and aryl C-N bonds. For instance, the starting triflate 477 could be efficiently transformed into the target system 478 by amination with aniline (Equation 133) <2005AGE403>. Annulation of (2-triflyloxy)phenethyl carbonates with amides in the presence of a palladium catalyst has been used as a route to various N-substituted indoline derivatives <2005OL4777>. 

Additions of various nucleophiles to vinyl selenoxides - and vinyl selenones have been described. Thus potassium hydroxide and amines add to vinyl selenones and directly produce epoxides and aziridines, respectively, whereas 3-methoxyoxetanes have been obtained from 7-hydroxy-a-alkenyl selenones and st ium methoxide (Scheme 111). ... 

Alkenyl and arylfluorides (F—C=C) are reactive and so one can imagine that the moiety of (F—C=X) (X=0, NR) should also be reactive. Acyl fluorides have greater stability than the corresponding chlorides toward neutral oxygen nucleophiles such as water and methanol, but appear to be equal reactivity toward anionic nucleophiles and amines [ 1 ]. Cyanuric fluoride 2 is a mild reagent for the preparation of acyl fluorides [2]. The protected amino acids can be transformed into the corresponding amino alcohols without racemization by the reduction of acyl fluorides 3 [3]. 

The aspects relevant to the use of rosin as such, or one of the derivatives arising from its appropriate chemical modification as monomer or comonomer [12-14], have to do with the synthesis of a variety of materials based on polycondensations and polyaddition reactions of structures bearing such moieties as primary amines, maleimides, epoxies, alkenyls and, of course, carboxylic acids. These polymers find applications in paper sizing, adhesion and tack, emulsification, coatings, drug delivery and printing inks. 

Trost et al. reported that the ruthenium-catalyzed reaction of the allenic alcohols and amines 234 with methyl vinyl ketone produced the 2-alkenyl heterocycles 235 in good to high yields (Scheme 76).149 This reaction proceeds via formation of the ruthenacycle 236, which could also exist as the jr-allyl species 237. 

Chain elongation and amination occur on alkenyl iodides, when amines are added as co-reactants. ... 

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