Halides examples

Deoxy-D-nbo-hexono-1,5-lactone 5-Amino-5-deoxy-D-mannono-1,5-lactam Acyl halides are named by changing the ending -onic acid to -onoyl halide Example ... 

Organic halides play a fundamental role in organic chemistry. These compounds are important precursors for carbocations, carbanions, radicals, and carbenes and thus serve as an important platform for organic functional group transformations. Many classical reactions involve the reactions of organic halides. Examples of these reactions include the nucleophilic substitution reactions, elimination reactions, Grignard-type reactions, various transition-metal catalyzed coupling reactions, carbene-related cyclopropanations reactions, and radical cyclization reactions. All these reactions can be carried out in aqueous media. 

Natural products containing the isoprene unit can be prepared in this way. Methyl famesoates have been synthesized from geranyl halides and 1-carbomethoxyallylnickel halides (example 4, Table III). 

Vinyl halides (example 17, Table VII) were first observed by Kroper to form acrylic esters by reaction with carbon monoxide under pressure and tetracarbonylnickel in methanol at 100°C. These reactions were later shown to occur under much milder conditions. Highly stereospecific reactions were observed c/s-vinyl halides gave cis-carbonylation products and trans-vinyl halides trans-carbonylation products (example 18, Table VII). Retention of configuration of alkyl substrates in carbonylation seems to be a general feature in carbon monoxide chemistry (193a). 

Allylic halides (example 19, Table VII) carbonylate under very mild conditions. An inverse effect of the CO pressure was observed in reaction with Ni(CO)4, CO dissociation being required to allow coordination of the substrate (168). 

Aromatic halides (example 21, Table VII) also react in the presence of Ni(0) complexes in alkaline media. Complex nickel carbonyl anions, such as Ni5(CO),22, Ni6(CO)122, Ni9(CO)182 (194) are formed which, being more nucleophilic, can attack aromatic halides. 

Because the reduction potential of ether is usually more negative than that of halides, examples that belong to this category are rather rare. Generally, cathodic reduction of ethers is similar to that of alcohols, and nonactivated ethers are not reducible under the conditions of electroreduction. Activated ethers such as benzylic and allylic ethers are elec-trochemically reduced to a limited extent (Scheme 7) [1, 15, 16]. Reduction of epoxides is usually difficult however, electroreductive cleavage of activated epoxides to the corresponding alcohols is reported [17, 18]. The cleavage of the C—O bond of ethers is more easily accomplished in anodic oxidation than in cathodic reduction, which is stated in Chapter 6. 

Both neutral and anionic phosphorus compounds are good nucleophiles toward alkyl halides. Examples of these reactions were already encountered in Chapter 2 in connection with the preparation of the valuable phosphorane and phosphonate intermediates used for Wittig reactions ... 

Although there are numerous investigations of concerted dissociative ET reported, particularly those involving alkyl and benzyl halides, examples of other molecular systems that undergo putative concerted dissociative ET are not as well documented. Peroxides and endoperoxides are another class of compounds where ET to the oxygen—oxygen bond has recently been shown conclusively to follow a concerted dissociative mechanism. The concerted nature of the dissociative ET is, in part, a result of the very weak 0—0 bond, which is a necessary condition, as illustrated by equation (41). 

Layered structures are extremely prevalent among transition metal halides. Examples of compounds adopting the cadmium iodide structure or the related cadmium chloride structure (Fig. 7.9) are ... 

An ester is formed when a nitrile is heated with an alcohol in the presence of concentrated sulphuric acid, thus providing a two-step synthesis of an ester from an alkyl halide. Examples are to be found in Expt 5.152. The reaction proceeds by way of an intermediate imino-ester (7) which is not usually isolated, but may be if so required.163... 

Substitution of halogen atoms for one or more hydrogen atoms on alkanes gives alkyl halides example structural formulas are given in Figure 1.17. Most of the commercially important alkyl halides are derivatives of alkanes of low molecular mass. A brief discussion of the uses of the compounds listed in Figure 1.17 is given here to provide an idea of the versatility of the alkyl halides. 

Gd2Cl (15, 16), Sc5Cl (]J), and Y r (18). It is not by accident that the halide examples are found among the metals with fewer valence electrons and larger metallic radii. In these structures the M-M and X-X distances must be equal along the chain, consequently the larger spacing required by Cl-Cl or Br-Br nonbonded contacts dictate lower M-M bond+orders. 

Initiation is facilitated by interaction of the Lewis acid with a second compound (called a cocatalyst) that can donate a proton or carbenium ion to the monomer. Typical eocatalysts are water, protonic acids, and alkyl halides. Examples of Lewis acid-cocatalyst interactions are given in reactions (9-29) and (9-32). The general reaction for... 

Aliphatic gem-dihalides require more vigorous conditions for hydrolysis than do the benzal halides. Examples are found in the treatment of certain 1,1-dichloroalkanes, like l,l-dichloro-3 methylbutane and 1,1-dichloro-3,3"dimethylbutane, with water and, in some cases, magnesium oxide for 4 hours at 200-300°. The aldehydes are formed in 60-96% yields (cf. method 222). 

Ferrocene-containing metal complexes have been reported over the years, and the topic has been reviewed (263). Again, the preferred method to prepare such complexes is the utilization of ferrocenyllithium with metal halides. Examples of bimetallic ferrocenyl compounds are known where the a--bonded metals are in both high and low formal oxidation states. 

Other amines must first be converted into their more strongly nucleophilic metal derivatives which are then treated with tin halides. Examples of the transmetallation reactions which occur are given in equations 16-6,4 16-7,5,6 16-8,7 16-9,8 16-10,9 16-1110 16-12,11 and 16-13.12 The metal is usually an alkali metal, most commonly lith-... 

The organotin thiolates (mercaptides) are usually prepared by substitution by a sulfur nucleophile at a tin centre. Suitable pairs of reactants are (1) thiol and tin oxide, alkox-ide, or amide, (2) thiol and tin halide in the presence of a base such as sodium hydroxide, sodium carbonate, ammonia, or triethylamine, or (3) metal thiolate and tin halide. Examples are shown in equations 17-20,33 17-21,33 and 17-22,34 and some of the common products are listed in Table 17-2. 

Many reactions are known for which addition of silane is accompanied by the elimination of a small molecule (H2, hydrocarbon, a different silane, hydrogen halide). Examples of such reactions are shown in equations 6-10 (Cp = r/5-C5Me5)18"22. Generally these reactions can be viewed as proceeding through successive oxidative addition and reductive elimination steps (or vice versa). 

Besides ethers, other compounds that form similar adducts accelerate the reaction of magnesium with an alkyl halide examples are dialkyl derivatives of elements of the Sixth Group (sulfur, selenium, and tellurium) and tertiary amines such as dimethylaniline, diethylaniline, pyridine, and quinoline. 

I. I. Plasma-Chemical Decomposition of Hydrogen Halides Example of HBr Dissociation with Formation of Hydrogen and Bromine... 

Clusters of the group V-VII metals in high formal oxidation states, stabilised by 7t-donor ligands such as oxide, sulphide, or halides. Examples here include [Nb6Cli2] +, [WeBrgJ +and [Re3Cl9] +. 

Alkyl hahdes are classified as being primary (1°), secondary (2 ), or tertiary (3°). This classification is based on the carbon atom to which the halogen is directly attached. If the carbon atom that bears the halogen is attached to only one other carbon, the carbon atom is said to be a primary carbon atom and the alkyl balide is classified as a primary alkyl halide. If the carbon that bears the halogen is itself attached to two other carbon atoms, then the carbon is a secondary carbon and the alkyl halide is a secondary alkyl halide. If the carbon that bears the halogen is attached to three other carbon atoms, then the carbon is a tertiary carbon and the alkyl halide is a tertiary alkyl halide. Examples of primary, secondary, and tertiary alkyl halides are the following ... 

---