Alkyl halides functional group

Acid chlorides also couple smoothly with lower-order zinc cyanocuprates (equation 59) to give ketones in high yields. Although most acid chloride substrates employed have been simple ones, alkenes, benzylic and alkyl chloride functional groups have been present in the acyl halide without incident25. 

Synthesis of functional latex particles via seeded-emulsion copolymerization incorporation of a functional monomer bearing an alkyl halide initiating group for ATRP... 

A saturated alkyl group does not exhibit functionality. It is not a d -synthon, because the functional groups, e.g. halide or metal ions, are lost in the course of the reaction. It functions as an alkyl synthon. Alkenyl anions (R. West, 1961) on the other hand, constitute d -synthons, because the C = C group remains in the product and may be subject to further synthetic operations. 

Organic compounds are grouped into families according to the functional groups they contain Two of the most important families are alcohols and alkyl halides Alco hols and alkyl halides are especially useful because they are versatile starting materials for preparing numerous other families Indeed alcohols or alkyl halides—often both— will appear m virtually all of the remaining chapters of this text... 

It IS convenient m equations such as this to represent generic alcohols and alkyl halides as ROH and RX respectively where R stands for an alkyl group In addition to con venience this notation lets us focus more clearly on the functional group transformation that occurs the OH functional group of an alcohol is replaced as a substituent on car bon by a halogen usually chlorine (X = Cl) or bromine (X = Br)... 

While developing the connections between structure reaction and mechanism we will also extend the fundamentals of lUPAC nomenclature to functional group families beginning with alcohols and alkyl halides... 

The lUPAC rules permit alkyl halides to be named m two different ways called func twnal class nomenclature and substitutive nomenclature In functional class nomencla ture the alkyl group and the halide (fluoride chloride bromide or iodide) are desig nated as separate words The alkyl group is named on the basis of its longest continuous chain beginning at the carbon to which the halogen is attached... 

Alcohols and alkyl halides are classified as primary secondary or tertiary according to the degree of substitution of the carbon that bears the functional group (Section 2 13) Thus primary alcohols and primary alkyl halides are compounds of the type RCH2G (where G is the functional group) secondary alcohols and secondary alkyl halides are compounds of the type R2CHG and tertiary alcohols and tertiary alkyl halides are com pounds of the type R3CG... 

Many of the properties of alcohols and alkyl halides are affected by whether then-functional groups are attached to primary secondary or tertiary carbons We will see a number of cases m which a functional group attached to a primary carbon is more reac live than one attached to a secondary or tertiary carbon as well as other cases m which the reverse is true... 

The carbon that bears the functional group is sp hybridized m alcohols and alkyl halides Figure 4 1 illustrates bonding m methanol The bond angles at carbon are approximately tetrahedral as is the C—O—H angle A similar orbital hybridization model applies to alkyl halides with the halogen connected to sp hybridized carbon by a ct bond Carbon-halogen bond distances m alkyl halides increase m the order C—F (140 pm) < C—Cl (179 pm) < C—Br (197 pm) < C—I (216 pm)... 

Table 4 2 lists the boiling points of some representative alkyl halides and alcohols When comparing the boiling points of related compounds as a function of the alkyl group we find that the boiling point increases with the number of carbon atoms as it does with alkanes... 

Alkyl halides are such useful starting materials for preparing other functional group types that chemists have developed several different methods for converting alcohols to alkyl halides Two methods based on the inorganic reagents thionyl chloride and phosphorus tnbromide bear special mention... 

Thionyl chloride and phosphorus tribromide are specialized reagents used to bring about particular functional group transformations For this reason we won t present the mechanisms by which they convert alcohols to alkyl halides but instead will limit our selves to those mechanisms that have broad applicability and enhance our knowledge of fundamental principles In those instances you will find that a mechanistic understand mg IS of great help m organizing the reaction types of organic chemistry... 

Chemical reactivity and functional group transformations involving the preparation of alkyl halides from alcohols and from alkanes are the mam themes of this chapter Although the conversions of an alcohol or an alkane to an alkyl halide are both classi tied as substitutions they proceed by very different mechanisms... 

This concludes discussion of our second functional group transformation mvolv mg alcohols the first was the conversion of alcohols to alkyl halides (Chapter 4) and the second the conversion of alcohols to alkenes In the remaining sections of the chap ter the conversion of alkyl halides to alkenes by dehydrohalogenation is described... 

Table 8 1 illustrates an application of each of these to a functional group transfer matron The anionic portion of the salt substitutes for the halogen of an alkyl halide The metal cation portion becomes a lithium sodium or potassium halide... 

Representative Functional Group Transformations by Nucleophilic Substitution Reactions of Alkyl Halides... 

Sulfonate esters are subject to the same limitations as alkyl halides Competition from elimination needs to be considered when planning a functional group transforma tion that requires an anionic nucleophile because tosylates undergo elimination reactions just as alkyl halides do... 

Nitriles contain the —C=N functional group We have already discussed the two mam procedures by which they are prepared namely the nucleophilic substitution of alkyl halides by cyanide and the conversion of aldehydes and ketones to cyanohydrins Table 20 6 reviews aspects of these reactions Neither of the reactions m Table 20 6 is suitable for aryl nitriles (ArC=N) these compounds are readily prepared by a reaction to be dis cussed m Chapter 22... 

The value of alkyl halides as starting materials for the preparation of a variety of organic functional groups has been stressed many times In our earlier discussions we noted that aryl halides are normally much less reactive than alkyl halides m reactions that involve carbon-halogen bond cleavage In the present chapter you will see that aryl halides can exhibit their own patterns of chemical reactivity and that these reac tions are novel useful and mechanistically interesting... 

Cyclo acylations leadUy take place in intermoleculai acylations involving bifunctional acylating agents. Both functional groups may be acyl (as in the case of a,CO-diacyl halides) or one may be an alkylating group (as in unsaturated acyl halides or certain haloacyl halides) (18). 

Historically, simple Vz-alkyl ethers formed from a phenol and a halide or sulfate were cleaved under rather drastic conditions (e.g., refluxing HBr). New ether protective groups have been developed that are removed under much milder conditions (e.g., via nucleophilic displacement, hydrogenolysis of benzyl ethers, and mild acid hydrolysis of acetal-type ethers) that seldom affect other functional groups in a molecule. 

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