Alkyl Halides and Nucleophilic Substitution

Alkyl halides are organic molecules containing a halogen atom X bonded to an sp hybridized carbon atom. Alkyl halides are classified as primary (1°), secondary (2°), or tertiary (3°) depending on the number of carbons bonded to the carbon with the halogen. 

Alkyl halides have the general molecular formula CnHgn+iX, and are formally derived from an alkane by replacing a hydrogen atom with a halogen. 

Allylic halides and benzylic halides have halogen atoms bonded to sp hybridized carbon atoms and do undergo the reactions described in Chapter 7. Allylic halides have X bonded to the carbon atom adjacent to a carbon-carbon double bond, and benzylic halides have X bonded to the carbon atom adjacent to a benzene ring. The synthesis of allylic and benzylic halides is discussed in Sections 15.10 and 18.13, respectively. 

Four types of organic halides (RX) having X near a jt bond 

These organic halides are unreactive in the reactions discussed in Chapter 7. 

Nucleophilic substitution is one of the two main reactions of alkyl halides. A nucleophile replaces a leaving group on an sp hybridized carbon. 

The electron pair in the C-Nu bond comes from the nucleophile. 

One a bond is broken and one a bond is formed. There are two possible mechanisms SnI and Sn2. 

Study Guide/Solutions Manual to accompany Organic Chemistry, 3rd Edition 

The best leaving group is the weakest base. Leaving group ability increases across a row and down a column of the periodic table (7.7). 

Adrenaline (or epinephrine), a hormone secreted by the adrenal gland, increases blood pressure and heart rate, and dilates lung passages. Individuals often speak of the rush of adrenaline when undertaking a particularly strenuous or challenging activity. Adrenaline is made in the body by a simple organic reaction called nudeophilic substitution. In Chapter 7 we learn about the mechanism of nucleophilic substitution and how adrenaline is synthesized in organisms. 

This is the first of three chapters dealing with an in-depth study of the organic reactions of compounds containing C-Z a bonds, where Z is an element more electronegative than carbon. In Chapter 7 we learn about alkyl halides and one of their characteristic reactions, nucleophilic substitution. In Chapter 8, we look at elimination, a second general reaction of alkyl halides. We conclude this discussion in Chapter 9 by examining other molecules that also undergo nucleophilic substitution and elimination reactions. 

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To check this possibility we performed experiments with different concentrations of NaBr in the NaY zeolite. Table 2 presents the results. It can be seen that upon increasing the amount of NaBr impregnated on NaY, there is preference to formation of the cyclobutyl bromide over allylcarbinyl bromide, indicating that the relative position between the bromide ions and bicyclobutonium governs the product distribution. Hence, zeolites may act as solid solvent, favoring ionization of alkyl halides and nucleophilic substitution reactions. In contrast to liquid solvents, where solvation is mostly uniform, the zeolite surface seems to provide unsymmetrical solvation of the cations, leading to product distribution that is different from solution. 

Assign R or 5 to a Stereogenic Center 173 Find and Draw All Possible Stereoisomers for a Compound with Two Stereogenic Centers 177 Alkyl Halides and Nucleophilic Substitution Name an Alkyl Halide Using the lUPAC System 232... 

Alkoxides are useful reagents they are used as powerful bases (stronger than hydroxide). Sodium t-butoxide and ethyl bromide (CH3CH2Br) are mixed together to give CeHi O. This reaction illustrates nucleophilic substitution. Ethyl bromide is an alkyl halide, and nucleophilic substitution is typical of such organic compounds. Nucleophilic substitution may be generalized as... 

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