- Stereoselective geminal difunctionalization of vinyl arenes mediated by the bromonium ion
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An anti-Markovnikov geminal oxyamination of styrenyl alkenes in an intermolecular fashion using the umpolung strategy mediated by the bromonium ion is reported. Isotope labeling studies confirm the migration of the phenyl group in the semipinacol rearrang
- Balaji, Pandur Venkatesan,Chandrasekaran, Srinivasan
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supporting information
p. 70 - 72
(2014/01/06)
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- Stereo- and regioselective synthesis of polysubstituted chiral 1,4-oxazepanes
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The number of cyclic molecular scaffolds available to medicinal chemists remains limited, and simple structures such as oxazepanes are still made using multistep procedures, including a number of protection/deprotection steps and purifications. We report
- Bezanson, Michelle,Pottel, Joshua,Bilbeisi, Rana,Toumieux, Sylvestre,Cueto, Micka?l,Moitessier, Nicolas
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p. 872 - 885
(2013/04/10)
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- Gold-catalyzed direct activation of allylic alcohols in the stereoselective synthesis of functionalized 2-vinyl-morpholines
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Alcohol versus alcohol: A highly stereocontrolled synthesis of substituted morpholines is realized by means of gold-catalyzed dehydrative allylic cyclization of diols (see scheme for one example; segphos = 5,5′-bis[di(3, 5-di-tert-butyl-4-methyoxyphenyl)phosphine]-4,4′-bi-1,3-benzodioxole). The present methodology represents one of the few examples of enantioselective gold-catalyzed transformations involving unactivated alkenes. Copyright
- Bandini, Marco,Monari, Magda,Romaniello, Alessandro,Tragni, Michele
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supporting information; body text
p. 14272 - 14277
(2011/03/19)
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- Stereoselective synthesis of certain trifluoromethyl-substituted alcohols
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A process for stereoselective synthesis of a compound of Formula (I) wherein R1, R2, R3, R4, and R5 are as described herein.
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Page/Page column 7-8
(2010/02/14)
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- Asymmetric total synthesis of the gastroprotective microbial agent AI-77-B
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An enantioselective total synthesis of the pseudopeptide microbial agent AI-77-B, which has shown potent antiulcerogenic properties, is described. The synthesis is convergent and involves the assembly of a dihydroisocoumarin fragment and a hydroxy amino acid. The dihydroisocoumarin derivative was synthesised by means of a Diels-Alder reaction between 1-methoxy-1,3-cyclohexadiene and an alkynyl ester derivative as the dienophile. The alkynyl ester was obtained stereoselectively by two different synthetic routes: (1) A stereoselective allylation of leucinal, and (2) a titanium enolate-mediated anti-aldol reaction with trichlorobutyraldehyde, a novel homopropargylaldehyde equivalent. The stereocentres of the hydroxy amino acid moiety were generated through a titanium enolate-mediated syn-aldol reaction, Curtius rearrangement, and application of Dondoni's aldehyde homologation. Condensation of the dihydroisocoumarin and hydroxy amino acid moieties and subsequent removal of the protecting groups furnished optically active AI-77-B. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).
- Ghosh, Arun K.,Bischoff, Alexander,Cappiello, John
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p. 821 - 832
(2007/10/03)
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- Transition-state mimetics for HIV protease inhibitors: Stereocontrolled synthesis of hydroxyethylene and hydroxyethylamine isosteres by ester- derived titanium enolate syn and anti-aldol reactions
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Stereocontrolled syntheses of hydroxyethylene dipeptide isostere and aminoalkyl epoxides for hydroxyethylamine isosteres are described. The stereochemistry of both stereogenic centers of the aminoalkyl epoxides 10 and 15 as well as they γ-lactone 17 was assembled by our recently developed highly selective ester-derived titanium enolate aldol reactions. The Ti- enolate of 6 reacted with (benzyloxy)acetaldehyde and cinnamaldehyde to provide the syn-aldol product 7 and anti-aldol product 12, respectively. Removal of the chiral template followed by Curtius rearrangement of the resulting acid provided the desired amine functionality. The present syntheses represent practical and enantioselective entry to a range of other dipeptide isosteres, which are not limited to amino acid derived substituents.
- Ghosh,Fidanze
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p. 6146 - 6152
(2007/10/03)
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- Highly stereoselective reduction of α-keto esters: Utility of cis-1-arylsulfonamido-2-indanols as chiral auxiliaries
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The reduction of α-keto esters bearing cis-1-arylsulfonamide-2-indanol derivatives proceeded with high diastereoselectivities providing the corresponding α-hydroxy esters in excellent yields. The chiral auxiliary group is removed under mild basic conditions and recovered.
- Ghosh,Ghosh, Arun K.,Chen,Yan, Chen
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p. 6811 - 6814
(2007/10/02)
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