Amination alkenes

The double bond of an enamine (alkene + amine) is much more nucleophilic than a typical alkene double bond. Assuming that the nitrogen atom in an enamine is. -hybridized, draw an orbital picture of an enamine, and explain why the double bond is electron-rich. 

Heterolytic catalysis is promoted by W6+, Ti4+, Cr3+, V5+, and many Mo6+ complexes. These complexes do not normally react with peroxides. However, in the presence of electron-rich molecules, such as alkenes, amines, sulfides, etc., oxygen insertion in the reactant occurs. For example,... 

The reactivity of heterocyclic systems with carbenes, generated under phase-transfer catalytic conditions, has been reviewed for the period up to 1983 [1]. Most unsaturated non-heteroaromatic systems react with carbenes in the manner expected of alkenes, amines, amides, ketones, etc. (see Sections 7.3,7.5 and 7.6). 

Hosokawa, Murahashi, and coworkers demonstrated the ability of Pd" to catalyze the oxidative conjugate addition of amide and carbamate nucleophiles to electron-deficient alkenes (Eq. 42) [177]. Approximately 10 years later, Stahl and coworkers discovered that Pd-catalyzed oxidative amination of styrene proceeds with either Markovnikov or anti-Markovnikov regioselectivity. The preferred isomer is dictated by the presence or absence of a Bronsted base (e.g., triethylamine or acetate), respectively (Scheme 12) [178,179]. Both of these reaction classes employ O2 as the stoichiometric oxidant, but optimal conditions include a copper cocatalyst. More recently, Stahl and coworkers found that the oxidative amination of unactivated alkyl olefins proceeds most effectively in the absence of a copper cocatalyst (Eq. 43) [180]. In the presence of 5mol% CUCI2, significant alkene amination is observed, but the product consists of a complicated isomeric mixture arising from migration of the double bond into thermodynamically more stable internal positions. 

An interesting new method for the preparation of the methoxycarbonyl (and related) compound (35) involves the hydroboration-carbon monoxide insertion in bis-alkenic amines (34). The best reagent for this process is thexylborane, followed by cyanidation (82JOC1494). The yields are not very good and seven-membered ring compounds (36) can also be formed, but the procedure is short and simple. 

Secondary amino compounds of the type R2N—H add to aldehyde and ketone carbonyl groups in an acid-catalyzed reaction in much the same way as do RNH2 compounds—with one important difference. The product contains the structural unit C=C—N rather than C—C—N and because there is a carbon-carbon double bond, such a substance is called an enamine (alkene + amine). An example is ... 

Cyclizations of alkenic amines and imines using organoiron complexes to generate bicyclic 3-lactams are discussed in Chapter 3.1 of this volume. Examples of heterocyclizations of alkenic NA/-dialkylamine and pyridine derivatives to form cyclic quaternary ammonium salts are cited in the Staninets review.Ic A cyclization of an enol thioether has been used to generate a thiazolidine intermediate used in cephalosporin synthesis (equation 131).262... 

As stated above, aliphatic amines are potent ligands for electrophilic transition metals and are efficient catalyst poisons in attempted alkene animation reactions. However, tosylation of the basic amino group greatly reduces its complexing ability, yet does not compromise its ability to nucleophilically attack complexed alkenes. Thus, a variety of alkenic tosamides efficiently cyclized under palladium(II) catalysis producing N-tosylenamines in excellent yield (equations 17 and 18).32 Again, this alkene amination proceeded through an unstable a-alkylpalladium(II) species, which could be intercepted by carbon monoxide, to result in an overall aminocarbonylation of alkenes. With ureas of 3-hydroxy-4-pentenyl-amines (Scheme 7), this palladium-catalyzed process was quite efficient but it was somewhat less so with... 

Complexes between tetranitromethane (which is a powerful electron acceptor) and different electron donors (aromatic substrates, alkenes, amines, sulphides, ethers) may be observed and isolated as moderately stable coloured complexes (if stored in the dark). These complexes are usually classified as CT complexes. Irradiation of complexes between alkenes and trinitromethane forms interesting products, which are derived from the nucleophilic attack of the trinitromethide. 

Based on their chemical structure, the organic chemicals were divided into a number of categories alkanes, alkenes, amines, aromatic hydrocarbons, benzenes, carboxylic acids, halides, phenols, and sulfonic acid. Linear regression analysis has been applied using the method of least-squares fit. Each correlation required at least three datapoints, and the parameters chosen were important to ensure comparable experimental conditions. Most vital parameters in normalizing oxidation rate constants for QSAR analysis are the overall liquid volume used in the treatment system, the source of UV light, reactor type, specific data on substrate concentration, temperature, and pH of the solution during the experiment. 

Vapor pressure selectivity and other phase-specific reactions might be useful for achieving selectivity not possible by conventional means. The method makes reactive radicals such as H atoms available in preparatively useful amounts using only inexpensive apparatus. Alkanes can be functionalized in a variety of ways. Several unusual compounds are also available in this way from a variety of alcohols, alkenes, amines, carboxylic acids, ethers, and fluorocarbons. 

Electronically excited carbonyl chromophores in ketones, aldehydes, amides, imides, or electron-deficient aromatic compounds may act as electron acceptors (A) versus alkenes, amines, carboxylates, carboxamides, and thioethers (D, donors). In addition, PET processes can also occur from aromatic rings with electron-donating groups to chloroacetamides. These reactions can be versatile procedures for the synthesis of nitrogen-containing heterocyclic compounds with six-membered (or larger) rings [2],... 

Carbonyl compounds undergo PET reaction with electron donating substrates viz., alkenes, amines and thio-compounds. Except in the photoreactions with electron poor alkenes, such as acrylonitrile [165,166], carbonyl compounds usually act as an electron accepting partners. The chemical reaction pathways... 

Alkene Amine Time Reducing //-Hydroxy Amine b d.r. Yield Ref... 

Alkene Amine Oxidant Workup Product d.r. Yield... 

---