Epoxide opening amine

Reaction of pyrazole with phenethyl bromide 84 Ring opening of an epoxide by amines 85... 

The enantioseiective hydrogenation of a-amino ketones has been applied extensively to the synthesis of chiral drugs such as the / -agonist SR 58611 (Sanofi Cie). m-Chlorstyreneoxide was obtained via carbene-induced ring closure of the amino alcohol. Epoxide-opening by a chiral amine obtained via a ruthenium-catalyzed hydrogenation of an enamide has led to the desired compound where... 

The asymmetric lithiation/substitution of Af-Boc-Af-(3-chloropropyl)-2-alkenylamines 395 by w-BuLi/(—)-sparteine (11) provides (5 )-Af-Boc-2-(alken-l-yl)pyrrolidines 397 via the allyllithium-sparteine complexes 396 (equation 106) . Similarly, the piperidine corresponding to 397 was obtained from the Af-(4-chlorobutyl)amine. Intramolecular epoxide openings gave rise to enantioenriched pyrrolidinols. Beak and coworkers conclude from further experiments that an asymmetric deprotonation takes place, but it is followed by a rapid epimerization a kinetic resolution in favour of the observed stereoisomer concludes the cyclization step. 

Aziridines may be prepared by the intramolecular nucleophilic opening of epoxides by amines and their derivatives (84CAR(130)103,92T5639,92TL487,92TL5351) (Scheme 15). 

The effect of these chemical changes on the reaction of the amine functional groups of the silane with the epoxy resin matrix is seen in Fig. 4. The expected reaction is the opening of the epoxide by amine hydrogens to form hydroxy groups, as shown below ... 

The alkoxycarbonyl group does not have a strong directing effect on the ring opening of epoxides by amines (Scheme 4.76), and steric or electronic effects of the other substituents can be more important to the outcome of these reactions. The... 

An inversion temperature was found for the ring opening of meso-epoxides by amines in dichloromethane.23 These reactions, which were catalysed by samarium iodobinaphthoxide, gave amino alcohols in high enantiomeric excess. The inversion temperature was thought arise because the reaction can occur with two different solvation clusters. 

Ans. Heck reaction and Sharpless epoxidation followed by opening of the epoxide with amine (see W. A. Herrmann et al., Angew. Chem. Int. Ed., 1997, 36, 1049-1067). 

Another ring forming reaction uses an initial epoxide opening by the amine of an amino alcohol to generate a ring opened product which was subsequently converted to a quinazoline ring system <07JOC1492>. 

Functionality adjacent to the epoxide can modify its reactivity. For example, 2,3-epoxy sulfides can be converted to a thiiranium species upon treatment with TMS triflate. This intermediate reacts with 0-silyl amides regiospeci-fically to form l-substituted-3-hydroxy-2-thioethers. Simple primary amines undergo polyalkylation, but imines can be used as an indirect amine equivalent <1996T3609>. Nitriles react with functionalized oxiranes in a regioselective manner in a tandem epoxide opening-Ritter reaction (Equation 17) <2005JOC7447>. 

Chiral amino alcohols can be prepared by reaction of chiral epoxides with amines. Enantiopure (25, 3.R)-2,3-epoxy-3-phenylpropanol anchored to Merrifield resin has been used for ring-opening with secondary amines in the presence of lithium perchlorate to afford polymer-supported chiral amino alcohols 47 (Eq. 18) [56], By analogy, (2i ,35)-3-(cis-2,6-dimethylpiperidino)-3-phenyl-l,2-propanediol has been anchored to a 2-chlorotrityl chloride resin (48). Although this polymer had high catalytic activity in the enantioselective addition of diethylzinc to aldehydes, the selectivity of the corresponding monomeric catalyst was higher (97 % ee) in the same reaction. 

Ring openings of epoxides with various nucleophiles are catalyzed by acid or base and are accompanied by configurational inversion on the substituted carbon (23). Posner found that y-alumina facilitated nucleophilic ring openings of epoxides with amines, alcohols, and carboxylates to give P-functionalized alcohols stereospecihcally (trans) in good yields under mild reaction conditions (24). This catalytic behavior of alumina was assumed to be due to the cooperative function of acidic and basic sites on alumina. 

Brill and co-workers used levoglucosane as a rigid scaffold to synthesise libraries both in solution [74] and solid phase [75]. The opening of epoxide 125 by different hydroxycarboxylic acid methyl esters catalysed by Lewis acid, followed by simultaneous new epoxide formation and ester hydrolysis gave the resulting free acid ready for attachment to the solid support. Epoxide opening reactions with alkoxides, amines and thiols were carried out on solid phase... 

Aromatic amines and epoxy groups may be determined by titration when present in the same sample. The former is carried out with 0.1 M of HC104 in glacial acetic acid, using Crystal Violet (150) as indicator, whereas the latter requires epoxide opening with HC1 and the presence of tetraethylammonium bromide250. 

Amino alcohols. Epoxide opening by amines catalyzed by SmClj is regioselective and stereoselective. The nucleophiles attack from the less substituted carbon atoms. 

Reactions of epoxides with amines, azides, hydrazines, etc., formation of N-heterocycles by epoxide ring opening 04ZOR11. 

Exposed to hydrolytic conditions at different pH (2, 6,10), tetraethyl oxiranylidene-l,l-diphos-phonate reacts very slowly with water. " The reaction of tetraethyl oxiranyhdene-l,l-diphosphonate with several primary amines, including -propylamine, cyclohexylamine, benzylamine, and ally-lamine, has been examined, and the phosphonyl phosphates were isolated as the major products in 40-63% yields (Scheme 4.38). It seems very likely that the formation of phosphonyl phosphates is the result of a rearrangement either in concert with (path a) or subsequent to (path b) the opening of the epoxide with amine and generation of an intermediate alkoxide ion. When di- -propylamine was used, a second product, ethenylidene-1-phosphonyl-1-phosphate, corresponding to the loss of amine by elimination, is formed (32%) in addition to aminoethyl-l-phosphonyl-1-phosphate (20%). ... 

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