- A novel approach to chiral, nonracemic pyrrolidines by 5-exo-trig diastereoselective radical cyclization on acrylamides derived from (-)-8- aminomenthol
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α,β-Unsaturated amides supported on perhydro-1,3-benzoxazines derived from (-)-8-aminomenthol as chiral auxiliaries undergo regio- and stereoselective 5-exo-trig radical cyclization leading to diastereomeric five-membered lactams. These cyclization products are transformed into enantiopure 3,4-disubstituted pyrrolidines by reduction with aluminum hydride followed by removal of the menthol appendage.
- Andres, Celia,Duque-Soladana, Juan P.,Pedrosa, Rafael
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p. 4282 - 4288
(2007/10/03)
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- Preparation of Silyl Enol Ethers Derived from α-Phenylseleno aldehydes and α-Phenylseleno ketones
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The best experimental conditions for the preparation of trimethylsilyl enol ethers 3 from α-phenylseleno aldehydes 1, compatible with a limited deselenenylation of the substrate, were studied.Starting from α-phenylseleno ketones 2, the enoxysilanes 4, bearing a vinylic PhSe group, are the major products when triethylamine is the base.Trimethylsilyl enol ethers 5 with an allylic PhSe group are also formed beside 4 when LDA or KH are used at lower temperatures.
- Ponthieux, Sylvain,Outurquin, Francis,Paulmier, Claude
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p. 9569 - 9580
(2007/10/02)
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- Preparations de composes α-arylselenocarbonyles a l'aide de morpholinoareneselenenamides
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The reactivity of the morpholinoareneselenenamides 1 which are readily prepared from various diaryldiselenides, is investigated.The selenenamides 1 are good α-selenenylating agents for aliphatic aldehydes, α-ketoesters and conjugated enals yielding the α-
- Lerouge, Patrice,Paulmier, Claude
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p. 1219 - 1224
(2007/10/02)
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- α-PHENYLSELENENYLATION D'ALDEHYDES - SYNTHESE SIMPLE D'α-CETOALDEHYDES A FONCTION CETONE PROTEGEE
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Morpholinophenylselenenamide 2 add to β-phenylselenoenamines 1a and yield β,β-bis(phenylseleno) enamines 4.These compound undergo hydrolysis to form bis(phenylseleno) ethanal 5a.Also, 2 react with enolic aldehydes to give α-phenylselenoaldehydes 3.This re
- Paulmier, Claude,Lerouge, Patrice
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p. 1557 - 1560
(2007/10/02)
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