Alcohols, tertiary synthesis

The classic ionic methods for the removal of an unwanted hydroxyl group are summarized in detail in the book by Larock [6]. One method involves—for primary and unhindered secondary alcohols—the synthesis of the corresponding mesylates or tosylates. These compounds are prepared readily and then transformed into the corresponding deoxy compounds by reduction [7], Alternatively, introduction of a thiolate or halogen by a nucleophilic reaction can also be used. These compounds can then be readily desulfurized or dehalogenated (Scheme 1). Tertiary alcohols present no problem either, because a... 

While tertiary alcohols, tertiary steroidal alcohols " and many benzylic alcohols - are converted smoothly to the fluorinated products, secondary substrates need more severe reaction conditions and primary alcohols do not give the reaction at all. An Organic Synthesis procedure for the preparation of the reagent and its application to the synthesis of 1-fluoro-adamantane has been published examples of fluorides 1 formed using this procedure are given. ... 

Other cleavage procedures listed in Section 5.3 include use of a Grignard reagent to generate alcohols, the synthesis of amines by cleavage with hydrazine (ADCC linker), and the generation of tertiary amines by Hoffmann-elimination (acrylic acid linker). 

Beilstein Handbook Reference) AI3-01288 Alcool butylique tertiaire Arconol BRN 0906698 Butanol tertiaire t-Butanol tert-Butanol t-Butyl alcohol t-Butyl hydroxide tert-Butyl alcohol tertiary-Butanol Caswell No. 124A CCRIS 4755 Dimethylethanol EINECS 200-889-7 HSDB 50 Methanol, trimethyl- Methyl-2-propanol NCI-C55367 TBA Trimethyl carbinol Trimethyl methanol. Registered by EPA as an antimicrobial, fungicide, herbicide and insecticide (cancelled). Crystals mp = 25.4° bp = 82,4° d = 0.7887 LDso (rat orl) = 3500 mg/kg, pulmonary toxicity at 25 ppm. Lancaster Synthesis Co. Mallinckrodt Inc Sigma-Aldrich Fine Chem. 

Migration of all three primary alkyl groups from boron to the one carbon unit under the influence of TFAA is possible and results in tertiary alcohols. The synthesis of tri- -hexylmethanol is formulated. 

Further study has been made of the use of the methylthiomethyl group for protection of alcohols in synthesis. Primary and secondary alcohols and tertiary alcohols are converted into methylthiomethyl ethers using dimethyl sulphoxide and AcgO, and de-protection is brought about under neutral conditions with a mercury(n) salt. Under these conditions, a 1,3-dithian moiety or a silyl ether grouping in the same molecule are unaffected. Protection of alcohols as 2-phenylselenoethyl ethers and their de-protection by oxidation has been proposed. ... 

Alcohols react with hydrogen halides to yield al kyl halides The reaction is useful as a synthesis of al kyl halides The reactivity of hydrogen halides de creases in the order HI > HBr > HCI > HF Alcohol re activity decreases in the order tertiary > secondary > primary > methyl... 

Tertiary alcohols can be prepared by a variation of the Grignard synthesis that uses esters as the source of the carbonyl group Methyl and ethyl esters are readily available and are the types most often used Two moles of a Grignard reagent are required per mole of ester the first mole reacts with the ester converting it to a ketone... 

When applied to the synthesis of ethers the reaction is effective only with primary alcohols Elimination to form alkenes predominates with secondary and tertiary alcohols Diethyl ether is prepared on an industrial scale by heating ethanol with sulfuric acid at 140°C At higher temperatures elimination predominates and ethylene is the major product A mechanism for the formation of diethyl ether is outlined m Figure 15 3 The individual steps of this mechanism are analogous to those seen earlier Nucleophilic attack on a protonated alcohol was encountered m the reaction of primary alcohols with hydrogen halides (Section 4 12) and the nucleophilic properties of alcohols were dis cussed m the context of solvolysis reactions (Section 8 7) Both the first and the last steps are proton transfer reactions between oxygens... 

Thiols can be prepared by a variety of methods. The most-utilised of these synthetic methods for tertiary and secondary thiols is acid-catalysed synthesis for normal and secondary thiols, the most-utilised methods are free-radical-initiated, alcohol substitution, or halide substitution for mercaptoalcohols, the most-utilised method is oxhane addition and for mercaptoacids and mercaptonitnles, the most-utilised methods are Michael-type additions. 

These studies show that the perfluoroalkyletherlithium compound shown in equation 42 has greater thermal stability than the perfluorooctyllithium, which must be prepared in situ. This in situ process has been very useful in the synthesis of other shorter chain perfluoroalkyllithium compounds Pentafluoroethyllithium can be conveniently prepared in this manner and reacts with numerous esters to yield tertiary alcohols [76, 77] in excellent yields. 

When applied to the synthesis of ethers, the reaction is effective only with primary alcohols. Elimination to form alkenes predominates with secondary and tertiary alcohols. 

An asymmetric synthesis has used the reduction of imonium salts to optically active tertiary amines with lithium aluminum alkoxy hydrides derived from optically active alcohols (538,539). 

The sluggishness of the reaction of TIPSOTf with tertiary alcohols can be exploited to advantage, as was the case in Magnus synthesis of strychnine. The equilibrium favors the tertiary hemiketal, but silylation favors the primary alcohol. 

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