- CaF2 catalyzed SN2 type chlorodehydroxylation of chiral secondary alcohols with thionyl chloride: A practical and convenient approach for the preparation of optically active chloroalkanes
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A CaF2 catalyzed chlorodehydroxylation of chiral secondary alcohols with thionyl chloride has been developed. The chlorination reaction is effective for a wide range of alcohols, generating the corresponding chloroalkanes in good yield with high optical purity with inversion of the original configuration of the alcohol.
- Zhang, Junjie,Wang, Huanxia,Ma, Yun,Wang, Youming,Zhou, Zhenghong,Tang, Chuchi
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p. 2261 - 2263
(2013/05/09)
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- Triphosgene-amine base promoted chlorination of unactivated aliphatic alcohols
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Unactivated α-branched primary and secondary aliphatic alcohols have been successfully transformed into their corresponding alkyl chlorides in high yields upon treatment with a mixture of triphosgene and pyridine in dichloromethane at reflux. These mild chlorination conditions are high yielding, stereospecific, and well tolerated by numerous sensitive functionalities. Furthermore, no nuisance waste products are generated in the course of the reactions.
- Villalpando, Andres,Ayala, Caitlan E.,Watson, Christopher B.,Kartika, Rendy
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p. 3989 - 3996
(2013/06/04)
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- Chlorination of aliphatic primary alcohols via triphosgene-triethylamine activation
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Activation of primary aliphatic alcohols with triphosgene and triethylamine mixtures afforded either alkyl chloride or diethylcarbamate products, and the switch in selectivity appeared to be driven by sterics. The reaction conditions to achieve this highly useful transformation were unexceptionally mild and readily tolerated by a wide range of sensitive functionalities.
- Ayala, Caitlan E.,Villalpando, Andres,Nguyen, Alex L.,McCandless, Gregory T.,Kartika, Rendy
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supporting information; experimental part
p. 3676 - 3679
(2012/09/08)
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- Nucleophilic substitution of 1-phenyl-2-phenyl telluropropane to yield 2-halo-1-phenylpropanes
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Mechanism of a novel transformation of the alkyl phenyltellurides to alkyl halides via nucleophilic substitution of the phenyltelluro group in organotelluriums is studied on the basis of kinetics and stereochemistry using the titled chiral substrate. The results obtained strongly suggest that the substitutions proceed via SN2 mechanism with Walden inversion and very low Arrhenius' energies of activation.
- Ogura, Fumio,Okada, Yoshiharu,Nishimura, Naoko,Hamamoto, Kenichiro,Miyakawa, Makoto,Otsubo, Tetsuo,Aso, Yoshio,Inoue, Shinobu,Tsutsui, Koji
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p. 203 - 210
(2007/10/03)
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- Retentive Friedel-Crafts Alkylation of Benzene with Optically Active 2-Chloro-1-phenylpropane and 1-Chloro-2-phenylpropane
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Alkylations of benzene with both (-)-2-chloro-1-phenylpropane (1) and (+)-1-chloro-2-phenylpropane (2) in the presence of Lewis acid gave the same products: (-)-1,2-diphenylpropane (3), 1,1-diphenylpropane, and polymeric materials. In these reactions, (-)-3 was obtained in 45-100percent optical yield and was not racemized under the conditions used. These results reveal that the reaction from 1 to 3 proceeds with retention of configuration and that from 2 to 3 with inversion. The stereochemistry of the alkylation with 1 is elucidated by the mechanism involving a neighboring phenyl ?-assisted cation; benzene attacks only the β-carbon of 1 from the side on which the previously attached chloride anion is located. The result of the reaction with 2 can be explained by a process involving the 1,2-shift of phenyl group in the ionization step of 2, followed by the formation of the same intermediate as in the reaction with 1. The mechanism of the overall reaction is discussed.
- Masuda, Shinji,Nakajima, Tadashi,Suga, Sohei
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p. 1089 - 1094
(2007/10/02)
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