Haloalkanes alcohols

Recognize a simple haloalkane, alcohol, ether, phenol, aldehyde, ketone, carboxylic acid, amine, amide, or ester, given a molecular structure. 

Chapters 1—10 begin a study of organic compounds by first reviewing the fundamentals of covalent bonding, the shapes of molecules, and acid-base chemistry. The structures and typical reactions of several important classes of organic compounds are then discussed alkanes, alkenes and alkynes, haloalkanes, alcohols and ethers, benzene and its derivatives, and amines, aldehydes, and ketones, and finally carboxylic acids and their derivatives. 

Alkylation is accomplished by use of haloalkanes, alcohols, or alkenes any species that can function as a carbocation precursor. The alkylation reaction is accompanied by two significant and limiting side reactions polyalkylation, due to ring activation by the added alkyl groups, and rearrangement of the intermediate carbocation. These lead to diminished yields, and mixtures of products that can be difficult to separate as shown here ... 

Alkane Alkene Alkyne Aromatic Haloalkane Alcohol Ether... 

When named as a substituent, the OH group is called hydroxy. This occurs when a functional group taking higher precedence, such as in hydroxycarboxylic acids, is present (see margin structure). Like haloalkanes, alcohols can be classified as primary, secondary, or tertiary. 

Variables a andZ are specific constants reported by Tsonopoulos for some alcohols and water (e.g., methanol a = 0.0878, b = 0.0560 and water a = 0.0279, b = 0.0229). Tsonopoulos also gives specific prediction methods for haloalkanes and water pollutants. 

The hydrocarbons are the basic framework for all organic compounds. Different classes of organic compounds have one or more of the hydrogen atoms replaced by other atoms or groups of atoms. All we need to be aware of at this stage are the three classes of compounds known as alcohols, carboxylic acids, and haloalkanes ... 

The names of organic compounds are based on the names of the parent hydrocarbons alcohols contain —OH groups, carboxylic acids contain —COOH groups, and haloalkanes contain halogen atoms. 

The catalyst is phosphoric acid. The laboratory synthesis of alcohols is by nucleophilic substitution of haloalkanes. 

The alcohol is 3-methyl-2-butanol. (b) The compound is both a ketone and a haloalkane. Identify the hydrocarbon chain and number the chain in the direction that gives the ketone group the lower number. The chain has five carbon atoms the ketone group is on the second carbon atom from one end, and the chlorine atom is on the fourth ... 

Haloalkanes may react with hydroxide ions, undergoing nucleophilic displacement of the halide ion to form an alcohol. 

Aqueous solutions are not suitable solvents for esterifications and transesterifications, and these reactions are carried out in organic solvents of low polarity [9-12]. However, enzymes are surrounded by a hydration shell or bound water that is required for the retention of structure and catalytic activity [13]. Polar hydrophilic solvents such as DMF, DMSO, acetone, and alcohols (log P<0, where P is the partition coefficient between octanol and water) are incompatible and lead to rapid denaturation. Common solvents for esterifications and transesterifications include alkanes (hexane/log P=3.5), aromatics (toluene/2.5, benzene/2), haloalkanes (CHCI3/2, CH2CI2/I.4), and ethers (diisopropyl ether/1.9, terf-butylmethyl ether/ 0.94, diethyl ether/0.85). Exceptionally stable enzymes such as Candida antarctica lipase B (CAL-B) have been used in more polar solvents (tetrahydrofuran/0.49, acetonitrile/—0.33). Room-temperature ionic liquids [14—17] and supercritical fluids [18] are also good media for a wide range of biotransformations. 

Reactions of Alcohols, Esters, Silyl Ethers, Epoxides, and Haloalkanes... 

Modifying the reaction medium to involve liquid ammonia with metallic lithium, f-butyl alcohol, and white phosphorus, to which is added the haloalkane, is reported to provide the primary alkylphos-phine derived from the haloalkane.19 Similar results are reported for the reaction of red phosphorus with sodium acetylides20 and by treatment of red phosphorus with sodium metal in an organic medium followed by the addition of two equivalents of f-butyl alcohol and the haloalkane.21 The latter approach is noteworthy in that moderate yields (45%) are obtained for primary phosphines derived from secondary haloalkanes (Figure 2.6). Mixtures of tertiary phosphines bearing one or two acetylenic linkages are produced in low yield ( 15%) by the reaction of lithium acetylides with white phosphorus in liquid ammonia followed by addition of a haloalkane.22... 

The highly hydrophilic alcohols, pentaerythritol and 2-ethyl-2-hydroxymethyl-propan-l,3-diol, can be converted into their corresponding ethers in good yields under phase-transfer catalytic conditions [12]. Etherification of pentaerythritol tends to yield the trialkoxy derivative and kinetics of the reaction have been shown to be controlled by the solubility of the ammonium salt of the tris-ether in the organic phase and the equilibrium between the tris-ether and its sodium salt [13]. Total etherification of the tetra-ol is attained in good yield when reactive haloalkanes are used, and tetra-rt-octylammonium, in preference to tetra-n-butylammonium, bromide [12, 13]. 

Method E The alcohol (25 mmol), powdered KOH or NaOH (25 mmol), and Aliquat (0.2 g, 0.5 mmol) are stirred for 10 min and n-C H,7Br (1.93 g, 10 mmol) is then added. The reaction mixture is worked up to yield the alkyl octyl ether as described in 3.I.I.D. Method F. Under microwave irradiation The alcohol (10 mmol), haloalkane (25 mmol),... 

Sulphonic esters have been obtained from the sulphonyl chlorides in high yields under mild conditions for a range of alcohols and phenols [e.g. 18, 19]. Of particular value is the protection of glycosides possessing a free hydroxyl group and hydroxy-steroids, which are tosylated readily under phase-transfer conditions [20-22]. Alkyl sulphinites have been obtained in a similar manner [23]. Alternatively, preformed tetra-rt-butylammonium sulphonates or their alkali metal salts have also been alkylated with haloalkanes or alkyl fluorosulphonates [24,25]. In contrast with more classical procedures, tosylation of alcohols, which are susceptible to E/Z-isomerism, e.g. Z-alk-2-en-l-ols, occurs with retention of their stereochemistry under phase-transfer catalysis [26]. 

Hydroboration of alkenes in non-ethereal solvent has been reported using diborane generated in situ from a quaternary ammonium borohydride and bromoethane (see Section 11.5). Almost quantitative yields of the alcohols are reported [e.g. 1 ]. As an alternative to the haloalkane, trimethylsilyl chloride has also been used in conjunction with the ammonium borohydride [2]. Reduction of the alkene to the alkane also occurs as a side reaction (<20%) and diphenylethyne is converted into 1,2-diphenylethanol (70%), via the intermediate /ra 5-stilbene. 

Haloalkanes are readily oxidized to the corresponding aldehydes or ketones. The best yields are attained with secondary alcohols and unsaturated hydroxyl groups [5]. a-Nitroketones, which are valuable intermediates in organic synthesis, are... 

In general, the rates of reduction by the ammonium salts are slower than those attained under normal conditions with the lithium salts, but the use of a non-ethereal solvent can be an advantage. Quaternary ammonium aluminium hydrides reduce ketones and amides effectively to alcohols and amines. Nitriles are also reduced to amines, whereas haloalkanes and arenes are reductively dehalogenated to give hydrocarbons in high yield [3]. 

Reduction of conjugated carbonyl compounds using stoichiometric amounts of the ammonium salt shows little advantage over the sodium salt in acidic methanol [11] with both reagents producing allylic alcohols (58-88% for acyclic compounds and 15-64% for cyclic compounds) by selective 1,2-reduction of the conjugated systems. Aldehydes, ketones and conjugated enones are also reduced by tetra-n-butylammonium cyanoborohydride in HMPA [11, 12], whereas haloalkanes and alkanesulphonic esters are cleaved reductively under similar conditions [13]. 

Optically pure alcohols are converted via their mesylates into the corresponding chiral haloalkanes with the opposite configuration (>70% with an optical purity 90%) by a liquiddiquid phase-transfer catalysed SN2 reaction (2.1.5) with the appropriate potassium halide [7]. The preparation of chiral fluorides normally requires more vigorous conditions (160°C, 14 h in an autoclave). By-products of the reaction are the alcohol and alkene. 

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