- A Unified and Desymmetric Approach to Chiral Tertiary Alkyl Halides
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Enantioenriched tertiary alkyl halides are prevalent in bioactive molecules and can serve as versatile synthetic intermediates to construct complex structures. While conventional access to these motifs often hinges on stereoselective carbon-halogen or carbon-carbon bond formation reactions, desymmetric approaches using halogenated and prochiral tetrasubstituted carbons are largely elusive in comparison. Here, we report that a suite of dinuclear zinc catalysts with a prolinol- or pipecolinol-derived tetradentate ligand can reductively desymmetrize a large collection of easily available halomalonic esters to α-halo-β-hydroxyesters. These polyfunctionalized tertiary alkyl fluorides, chlorides, and bromides proved to be useful intermediates toward fluorinated drug analogs and polyhalogenated monoterpenes. The facile intramolecular epoxidation of the chiral chloride and bromide products has also enabled expeditious access to natural products containing tertiary alcohol motifs.
- Huang, Zhongxing,Low, Kam-Hung,Zhang, Suihan,Zheng, Yin,Zi, Weiwei
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p. 1951 - 1961
(2022/02/09)
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- The Baylis-Hillman chemistry in aqueous media: A convenient synthesis of 2-methylenealkanoates and alkanenitriles
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A convenient, general and efficient synthesis of 2-methylenealkanoates and alkanenitriles is accomplished via the regioselective nucleophilic (SN2′) addition of hydride ion from NaBH4 to (2Z)-2-(bromomethyl)alk-2-enoates and 2-(bromomethyl)alk-2-enenitriles respectively in the presence of DABCO in environment friendly aqueous media. Synthesis of two hypoglycemic agents is also described.
- Basavaiah, Deevi,Kumaragurubaran, Nagaswamy
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p. 477 - 479
(2007/10/03)
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- Asymmetric synthesis of (R)-(+)-etomoxir via enzymatic resolution
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An asymmetric synthesis of (R)-(+)-etomoxir 3, employing enzymatic resolution of ethyl 2-alkyl-2,3-dihydroxypropionate using Amano AK via transacylation is reported. Copyright (C) 2000 Elsevier Science Ltd.
- Jew, Sang-Sup,Roh, Eun-Young,Baek, Eun-Young,Mireille, Labrouillere,Kim, Hyung-Ook,Jeong, Byeong-Seon,Park, Mi-Kyoung,Park, Hyeung-Geun
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p. 3395 - 3401
(2007/10/03)
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- Versatile synthesis of 2-aryloxyalkyl-oxirane-2-carboxylate: Syntheses of ethyl 2-[6-(3-alkoxyphenoxy)-hexyl]oxirane-2-carboxylates
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A versatile synthetic route to 2-aryloxyalkyl-oxirane-2-carboxylates as potential hypoglycemic agent has been developed via combination of dioxirane epoxidation of inactive olefin and facile aryl alkyl ether formation of the labile epoxy alcohol by Mitsun
- Suh, Young-Ger,Min, Kyung-Hoon,Back, So-Young,Chai, Jung-Hyeon
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p. 1527 - 1535
(2007/10/03)
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- Medicaments for the treatment of cardiac insufficiency
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The use of oxirane carboxylic acids having the formula I: STR1 in which R1 and R2 are independently selected from hydrogen, halogen, straight-chain or branched 1-4C alkyl groups, straight-chain or branched 1-4C alkoxy groups, nitro or trifluoromethyl; R3 is hydrogen or straight-chain or branched 1-4C alkyl; Y is --O--(CH2)m --, where m is zero or a whole number from 1 to 4, and n is a whole number from 2 to 8, or a pharmaceutically acceptable salt thereof, is disclosed for treating heart insufficiency.
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- Asymmetric synthesis of (R)-(+)-etomoxir
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An asymmetric synthesis of etomoxir 1, involving bromolactonization by using (S)-(-)-proline as a chiral auxiliary, is reported.
- Jew, Sang-Sup,Kim, Hyung-Ook,Jeong, Byeong-Seon,Park, Hyeung-Geun
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p. 1187 - 1192
(2007/10/03)
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- Phospholipase A2 inhibitors
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There is disclosed a method for the treatment of immunoinflammatory conditions, such as allergy, anaphylaxis, asthma and inflammation in mammals which comprises administering to a mammal so afflicated an effective amount of a compound having the formula:
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- SYNTHESES OF ENANTIOMERS OF 2--OXIRANE-2-CARBOXYLIC ACID
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The title compounds were prepared by an efficient route featuring novel reductions of an acid chloride and the Sharpless epoxidation of an allylic alcohol.
- Crilley, Martine M. L.,Edmunds, Andrew J. F.,Eistetter, Klaus,Golding, Bernard T.
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p. 885 - 888
(2007/10/02)
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- Phospholipase A2 inhibitors
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There is disclosed a method for the treatment of immunoinflammatory conditions, such as allergy, anaphylaxis, asthma and inflammation in mammals which comprises administering to a mammal so afflicted an effective amount of a compound having the formula: S
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- Phenalkoxyalkyl- and phenoxyalkyl-substituted oxiranecarboxylic acids, their use and medicaments containing them
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Phenalkoxyalky- and phenoxyalkyl-substituted oxiranecarboxylic acids of the formula STR1 wherein R1 denotes a hydrogen atom (--H), a halogen atom, a lower alkyl group, a lower alkoxy group, a nitro group or a trifluoromethyl group, R2 has one of the meanings of R1, R3 denotes a hydrogen atom (--H) or a lower alkyl group, Y denotes --O--(CH2)m --, m denotes O or an integer from 1 to 4, and n denotes an integer from 2 to 8, with the proviso that the sum of m and n is an integer from 2 to 8, and the salts of the acids are new compounds. They display a hypoglycaemic action in warm-blooded animals. Processes for the preparation of the new compounds and of the intermediate products required for their preparation are described.
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