Fert-butylation

Goldenberg L M, Williams G, Bryce M R, Monkman A P, Petty M C, Flirsch A and Sol A 1993 Electrochemical studies on Langmuir-Blodgett films of 1-fert-butyl-1,9-dihydrofullerene-60 J. Chem. Soc., Chem. Commun. 1310-12... 

The nature of the initiation step, which may occur in a variety of ways, is not known in all cases. Commonly used ethers such as ethyl ether, isopropyl ether, tetrahydrofuran, and i)-dioxane are particulady prone to form explosive peroxides on prolonged storage and exposure to air and light (see Peroxides AND PEROXY COMPOUNDS, ORGANIC), and should contain antioxidants (qv) to prevent their build-up. One of the exceptions to the peroxide forming tendency of ethers is methyl fert-alkyl ethers such as methyl fert-butyl ether [1634-04-4] (MTBE) and fert-amyl methyl ether [994-05-8] (TAME). Both have shown htde tendency if any to form peroxides (2,8). 

This procedure has also been used successfully in the acetylation of cumene and fert.-butyl benzene. At the low temperatures employed there is very little decomposition, as is shown by the small amount of high-boiling residue. 

The functionalized allene, DIMETHYL 2,3-PENTADIENEDIOATE, the first in the series, is an intriguing substrate for various addition and cycloaddition reactions. Finally, a new reagent, DI-ferf-BUTYL DICARBONATE, for he formation of A-f-BOC derivatives which eliminates the use o the hazardous fert-BUTYL AZIDOFORMATE (WARNING) is intrqduced. 

Chlorohydnns and 1,2-dichloro denvatives are obtamed by oxidation of alkenes with fert-butyl hypochlorite when the reaction is performed in acetic acid instead of water, chlorohydrm acetate is formed [Ji] (equation 25)... 

FIGURE 4.6 The mechanism of formation of fert-butyl chloride from tert-butyl alcohol and hydrogen chloride. 

FIGURE 4.10 Potential energy diagram for reaction of fert-butyl cation with chloride anion. 

The transition state for this step involves partial bond fonnation between fert-butyl cation and chloride ion. 

FIGURE 4.11 Combination of terf-butyl cation and chloride anion to give fert-butyl chloride. In-phase overlap between a vacant p orbital of (CHbIbC" and a filled p orbital of Cr gives a C—Cl CT bond. 

In agreement with the proposed mechanism, A"-fert-alkyI-substituted oxaziranes are stable tow ard alkali. 2-fert-Butyl-3-phenyloxazirane (9) is not attacked by standing at room temperature w ith sodium methoxidc solution for 12 hr. Thus, the oxazirane ring itself does not react with basic reagents. 

The rearrangement of 2-fert-butyl-3-phenyloxazirane to the isomeric nitrone is quantitative on refluxing 3 days in acetonitrile [Eq. (25)]. ... 

Allyl alcohol fert-Butyl alcohol Ethylene glycol... 

Amino groups are often protected as their tert-butoxycarbonvl amide, or Boc, derivatives. The Boc protecting group is introduced by reaction of the amino acid with di-fert-butyl dicarbonate in a nucleophilic acyl substitution reaction and is removed by brief treatment with a strong organic acid such as trifluoro-acetic acid, CF3C02H. 

Predict the product of the reaction of valine with the following reagents (a) CH3CH2OH, acid (b) Di-fert-butyl dicarbonate... 

In contrast, thermolysis of the N-unsubstituted 4,6-di-fert-butyl-2-azabicyclo[3.2.0]hepta-2,6-diene (3) yields 3,6-di-ter -butyl-3//-azepine (4).70t287,288... 

Methyl 3,6-di-fert-butyl-1 //-azepine-1 -carboxylate (8), on heating with one equivalent of methyl azidoformate, yields a separable mixture of 2,6-and 2,8-diazabicyclooctadienes 10 and 11.145 Initial addition of the nitrene to C4-C5 of the azepine ring, followed by a [1,3]-C or [1,3]-N shift in the resulting azahomoazepine 9, accounts for the products. 

In the case of an aromatic 7t-nucleophile, a dramatic reversal of diastercoscleetivity is found on going from a phenyl to a cyclohexyl or fert-butyl substituent, which is attributed to a balanee of. syn-axial and A(1,3) interactions, while a boat-like transition state may also play a role149. 

Buten-2-ol, 3-bromo-2-methyl, acetate, 35 fert-Butyl alcohol, potassium salt [2-Pro-panol, 2-methyl-, potassium salt], 29... 

The submitters obtained N-Boc-4-hydroxyproline methyl ester from Synthetech, Inc. [Albany, OR, (503) 967-6575] or Bachem California [Torrance, CA, (310) 530-1571] and dried THF over 4A molecular sieves for two days prior to use (Karl-Fischer titration gave 145 pg/mL water). The checkers purchased N-Boc hydroxyproline methyl ester (97%) and fert-butyl acetate (99+%) from Aldrich Chemical Co. and obtained THF (HPLC grade) from Fisher Scientific. 

GC assay of the organic layer showed no EIN(TMS)2 remaining after 15 min of stirring (GC conditions Restek RTX-1 column (30 m x 0.53 mm, 1 m film thickness), 2.53 mL/min, initial temperature 50°C, final temperature 300°C, rate 20 deg/min, injection temperature 200°C, detector temperature 350°C, injection volume 1 pL, inject sample neat retention times fert-butyl alcohol 1.4 min, THF 1.7 min, heptane 2.1 min, HN(TMS)2 2.6 min, ethylbenzene (present in commercial LHS) 3.1 min, te/ t-butyl acetate 4.0 min). Volume percents were determined based on standard solution counts. 

The concept of hyperconjugation arose from the discovery of apparently anomalous electron-release patterns for alkyl groups. By the field effect alone, the order of electron release for simple alkyl groups connected to an unsaturated system is fert-butyl > isopropyl > ethyl > methyl, and this order is observed in many phenomena. Thus, the dipole moments in the gas phase of PhCHa, PhC2Hs, PhCH(CHa)2, and PhC(CHa)a are, respectively, 0.37, 0.58, 0.65 and 0.700. ... 

In some molecules, the twist conformation is actually preferred. In all cis-2,5-di-fert-butyl-l,4-cyclohexanediol, hydrogen bonding stabilizes the otherwise high-energy form and 1,3-dioxane 89 exists largely as the twist conformation shown. Of course, in certain bicyclic compounds, the six-membered ring is forced to maintain a boat or twist conformation, as in norbornane or twistane. 

The same thing can be done for primary and secondary R by treating alkyl chloro-formates (ROCOCl) with tri-n-propylsilane in the presence of fert-butyl peroxide and by treating thiono ethers ROC(=S)W (where W can be OAr or other... 

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