- Asymmetric syntheses of a GPR40 receptor agonist via diastereoselective and enantioselective conjugate alkynylation
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Two asymmetric methods to synthesize a potent GPR40 receptor agonist are reported. Both synthetic routes utilize readily available, inexpensive starting materials and reagents. The first route relies on a highly diastereoselective conjugate alkynylation of an ephedrine-derived oxazepanedione acceptor. The second route features the enantioselective alkynylation of a Meldrum's acid-derived acceptor mediated by a chiral zinc cinchonidine reagent.
- Woo, Jacqueline C.S.,Cui, Sheng,Walker, Shawn D.,Faul, Margaret M.
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experimental part
p. 4730 - 4737
(2010/08/06)
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- Preparation of Mono-/Difluorinated Hydrocarbon Compounds
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Mono- or difluorinated hydrocarbon compounds are prepared from an alcohol or a carbonylated compound by reacting one of these with a fluorinating reagent, optionally in the presence of a base, the fluorinating agent comprising a pyridinium reactant having the following formula (F), wherein R0 is an alkyl or cycloalkyl radical:
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Page/Page column 7
(2009/09/28)
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- Pseudo Vilsmeier reagents a new protocol for regiospecific C-C bond formation in pyridines
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2-Fluoro- and 2,6-difluoropyridine are readily quaternised with methyl p-toluenesulfonate and methyl triflate respectively. These salts readily undergo substitution of fluorine by enamines, the difluoro-derivatives being capable of specific mono- or disubstitution in a symmetrical or unsymmetrical manner. The products reduced to give keto-1, 2, 3, 6-tetrahydropyridines, can be hydrosed to the corresponding ketopyridines or hydrogenated to give ketopiperidines.
- Yu, Chu-Yi,Taylor, David L.,Meth-Cohn, Otto
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p. 6661 - 6664
(2007/10/03)
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