Epoxide alkylation

Hie origin of tlie acceleration produced by BF in epoxide alkylation teactions has been examined tlieotetically [124], A plausible patliway for BF patLicipation in tlie epoxide-opening is sliown in Fig. 10.5. An epoxide/BF complex CPI may eti-countet tlie cuprate duster to form a ternary complex CP2, ot siidi a complex may... 

Figure 19. Perpendicularity of the PAH and the base. Conformations of trans-diols. The steric hindrance in a bay region will cause hydroxyl or other substituents (such as DNA) to lie in an axial orientation. Sites where this occurs are marked "a". Those sites where there is no steric hindrance are marked "ae" (axial or equatorial). The conclusion is that when a diol epoxide alkylates DNA the base on DNA will be bonded axially to the PAH group.

Epoxides alkylate by a nucleophilic displacement reaction that opens the ring (Eq. 5-19). 

Sauter, M. and Adam, W. (1995) Oxyfunctionalization of benzofurans by singlet oxygen, dioxiranes, and peracids chemical model studies for the DNA-damaging activity of benzofuran dioxetanes (oxidation) and epoxides (alkylation). Accounts of Chemical Research, 28 (7), 289-298. 

Two previous studies (Moser et al., 2007, 2006) explored the effects of synthetic compounds with hydrocarbon tail-group structures resembling those of FAME with attached bulky moieties on the CP and PP of SME. These studies examined novel fatty ethers made from the reaction of various alcohols (C2—Cm) with epoxidized alkyl oleates in the presence of sulfuric acid catalyst. Bulky esters (isopropyl and isobutyl) were chosen to further enhance the low temperature fluidity of the synthetic adducts produced. As the chain length of the ether moiety attached to the fatty backbone increased in length, a corresponding improvement in low temperature performance was noticed. Although the materials had improved low temperature properties over that of neat SME, none of the synthesized compounds demonstrated effectiveness in decreasing CP or PP when added to SME. 

The combined use of catalytic amounts of N-benzylquininium chloride (1) with hydroxide bases (NaOH or KOH) has been explored for a variety of phase transfer reactions, including epoxidations, alkylations, and Michael reactions. The degree of stereoselectivity in product formation induced by the reagent can vary widely. ... 

Peroxidases are synthetically important enzymes that can catalyze the enantioselective oxygenation of sulfides to sulfoxides, alkenes to epoxides, alkyl benzenes to benzylic... 

In Pd(0)-catalyzed isomerization reaction of epoxides, alkyl-substituted epoxides afford methyl ketones (path a, Scheme 11), whereas aryl-substituted epoxides give aldehydes or ketones via cleavage of the benzylic C-O bond (path b) [94]. 

Di- and trisubstituted epoxides. j3-Hydroxyselenides (1), prepared by the method illustrated above, can be converted into epoxides. Alkylation with methyl iodide in the presence of silver tetrafluoroborate gives the resulting salts (2), which are treated with potassium -butoxide in DMSO. An epoxide (3) and methyl phenyl selenide are formed by way of the betaine (a). Unfortunately, when two alkyl groups are attached to the carbon bearing the SeCeHs group. 

This experiment describes the lithiation of allyl trimethylsilane and the conversions of the lithio compound with trimethylchlorosilane and cyclohexanone, reactions that proceed with very high y-selectivity. For functionalizations with other electrophiles, e.g., epoxides, alkyl halides, and carbon dioxide, see Ref. [1] and literature cited in this paper. 

Opening of epoxides. Epoxides alkylate A-heterocycles such as indoles, pyrroles, imidazoles, and pyrazoles. For example, styrene oxide and indole give 2-(3-indolyl)-2-phenylethanol in 88% yield (room temperature, 7 days). 

Intramolecular alkylation of the amine formed can also occur to give cyclic compounds. Electrophiles include mesylate,tosylate, epoxide, alkyl hromide, sulfate, and imino ether (Scheme 38). 

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