- Modified Julia fluoroolefination: Selective preparation of fluoroalkenoates
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(Chemical Equation Presented) The modified Julia olefination reaction has been applied to develop a stereoselective synthesis of fluoroalkenoate derivatives from a fluorobenzothiazolyl sulfone and aldehydes or a ketone. The olefination reaction can be ach
- Pfund, Emmanuel,Lebargy, Cyril,Rouden, Jacques,Lequeux, Thierry
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- Stereoselective formation of (Z)-2-fluoroalkenoates via Julia-Kocienski reaction of aldehydes with pyrimidinyl-fluorosulfones
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The selective synthesis of fluoroalkenoates is reported from a pyrimidinyl fluorosulfone. This sulfone allowed the preparation of Z-fluoroalkenoates with very high stereoselectivity from both aromatic and aliphatic aldehydes. The nature of the heterocycle
- Larnaud, Florent,Pfund, Emmanuel,Linclau, Bruno,Lequeux, Thierry
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p. 5632 - 5639
(2015/03/30)
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- A facile and mild approach for stereoselective synthesis of α-fluoro-α,β-unsaturated esters from α-fluoro-β-keto esters via deacylation
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The highly stereoselective olefination reaction of α-fluoro-β-keto esters for the synthesis of α-fluoro-α,β-unsaturated esters has been developed. The olefination combines nucleophilic addition, intramolecular nucleophilic addition, and elimination in one step, as well as provides a facile synthetic approach to α-fluoro-α,β-unsaturated esters which are important units in many biologically active compounds and useful precursors in a variety of functional-group transformations.
- Qian, Jinlong,Yi, Wenbin,Lv, Meifang,Cai, Chun
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p. 127 - 132
(2015/02/02)
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- P[N(i-Bu)CH2CH2]3N: Nonionic Lewis base for promoting the room-temperature synthesis of α,β-unsaturated esters, fluorides, ketones, and nitriles using Wadsworth - Emmons phosphonates
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The bicyclic triaminophosphine P(RNCH2CH2) 3N (R = i-Bu, 1c) serves as an effective promoter for the room-temperature stereoselective synthesis of α,β-unsaturated esters, fluorides, and nitriles from a wide array of aromatic, aliphatic, heterocyclic, and cyclic aldehydes and ketones, using a range of Wadsworth-Emmons (WE) phosphonates. Among the analogues of 1c [R = Me (1a), i-Pr (1b), Bn (1d)], 1a and 1b performed well, although longer reaction times were involved, and 1d led to poorer yields than 1c. Functionalities such as cyano, chloro, bromo, methoxy, amino, ester, and nitro were well tolerated. We were able to isolate and characterize (by X-ray means; see above) the reactive WE intermediate species formed from 2b and 1c.
- Chintareddy, Venkat Reddy,Ellern, Arkady,Verkade, John G.
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supporting information; experimental part
p. 7166 - 7174
(2010/12/25)
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- Tandem reduction-olefination of triethyl 2-acyl-2-fluoro-2-phosphonoacetates and a synthetic approach to Cbz-Gly-Ψ[(Z)-CF{double bond, long}C]-Gly dipeptide isostere
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(Z)-α-Fluoro-α,β-unsaturated esters (Z)-7a-f were stereoselectively prepared by a tandem reduction-olefination of triethyl 2-acyl-2-fluoro-2-phosphonoacetates 6a-f with NaBH4 in EtOH. A concise synthesis of Cbz-Gly-Ψ[(Z)-CF{double bond, long}C]-Gly (26) as a dipeptide isostere was achieved via the tandem reduction-olefination of the corresponding 2-acyl-2-fluoro-2-phosphonoacetate 20.
- Sano, Shigeki,Kuroda, Yoko,Saito, Katsuyuki,Ose, Yukiko,Nagao, Yoshimitsu
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p. 11881 - 11890
(2007/10/03)
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- Asymmetric photodeconjugation: Highly stereoselective synthesis of α-fluorocarboxylic derivatives
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Irradiations of α-fiuoro-α,β-unsaturated esters lead to the corresponding α-fluoro-β,γ-unsaturated isomers in good yields. The reaction required the use of an achiral base (typically an amine) to promote the protonation of the photodienolic intermediate. By replacing the ethyl group with a diacetone-D-glucose moiety, the reaction can be carried out in a diastereoselective manner to furnish the deconjugated esters with similar yields and selectivities up to 95%. The adducts were submitted to osmylation conditions to deliver α-fluoro-β-hydroxy-butyrolactones in one single step.
- Bargiggia, Frédéric,Dos Santos, Sylvia,Piva, Olivier
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p. 427 - 437
(2007/10/03)
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- Simmons-Smith reactions of fluoroallyl alcohol derivatives
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Simmons-Smith reactions of fluoroallyl alcohols and their derivatives with excess Zn-Cu and CH2I2 or Et2Zn and CH2I2 provided fluorocyclopropane derivatives. Diastereoselective cyclopropanation of the
- Morikawa,Sasaki,Mori,Shiro,Taguchi
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p. 3189 - 3193
(2007/10/02)
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