- Detection of 2-substituted cyclobutanones as irradiation products of lipid-containing foods: Synthesis and applications of cis- and trans-2-(tetradec-5′-enyl)cyclobutanones and 11-(2′-oxocyclobutyl)-undecanoic acid
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cis- (3cis) and trans-2-(tetradec-5′-enyl)cyclobutanone (3trans) have been chemically synthesised and used in the unambiguous identification of the cis isomer 3cis in irradiated meat (example chicken) and fruit (example pa
- Hamilton, Lynne,Stevenson, M. Hilary,Boyd, Derek R.,Brannigan, Ian N.,Treacy, Alan B.,Hamilton, John T. G.,McRoberts, W. Colin,Elliott, Christopher T.
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- Highly selective iridium-catalyzed asymmetric hydrogenation of trifluoromethyl olefins: A new route to trifluoromethyl-bearing stereocenters
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Fluorine-containing compounds are useful in many applications ranging from pharmaceuticals to ferroelectric crystals. We have developed a new, highly enantioselective synthetic route to trifluoromethyl-bearing stereocenters in up to 96% ee via asymmetric hydrogenation using N,P-ligated iridium catalysts. We also hydrogenated an isomeric mixture of olefins; this reaction gave the hydrogenation product highly enantioselectively (87% ee), and only the E isomer was present after the reaction had reached 56% conversion.
- Engman, Mattias,Cheruku, Pradeep,Tolstoy, Paeivi,Bergquist, Jonas,Voelker, Sebastian F.,Andersson, Pher G.
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supporting information; experimental part
p. 375 - 378
(2009/11/30)
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- Iridium-catalyzed asymmetric hydrogenation yielding chiral diarylmethines with weakly coordinating or noncoordinating substituents
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Diarylmethine-containing stereocenters are present in pharmaceuticals and natural products, making the synthetic methods that form these chiral centers are important in industry. We have applied iridium complexes with novel N,P-chelating ligands to the asymmetric hydrogenation of trisubstituted olefins, forming diarylmethine chiral centers in high conversions and excellent enantioselectivities (up to 99% ee) for a broad range of substrates. Our results support the hypothesis that steric hindrance in one specific area of the catalyst is playing a key role in stereoselection, as the hydrogenation of substrates differing little at the prochiral carbon occurred with high enantioselectivity. As a result, excellent stereodiscrimination was obtained even when the prochiral carbon bore, for example, phenyl and p-tolyl groups.
- Tolstoy, Paeivi,Engman, Mattias,Paptchikhine, Alexander,Bergquist, Jonas,Church, Tamara L.,Leung, Abby W.-M.,Andersson, Pher G.
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supporting information; experimental part
p. 8855 - 8860
(2009/12/04)
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