87947-81-7Relevant academic research and scientific papers
Synthesis of Linear (Z)-α,β-Unsaturated Esters by Catalytic Cross-Metathesis. The Influence of Acetonitrile
Yu, Elsie C.,Johnson, Brett M.,Townsend, Erik M.,Schrock, Richard R.,Hoveyda, Amir H.
supporting information, p. 13210 - 13214 (2016/10/30)
Kinetically controlled catalytic cross-metathesis reactions that generate (Z)-α,β-unsaturated esters selectively are disclosed. A key finding is that the presence of acetonitrile obviates the need for using excess amounts of a more valuable terminal alken
3,5-Bis(trifluoromethyl)phenyl sulfones for the highly stereoselective Julia-Kocienski synthesis of α,β-unsaturated esters and weinreb amides
Alonso, Diego A.,Fuensanta, Monica,Gomez-Bengoa, Enrique,Najera, Carmen
experimental part, p. 2915 - 2922 (2009/04/10)
The 3,5-bis(trifluoromethyl)phenyl (BTFP) sulfones tert-butyl α-(BTFPsulfonyl)acetate (4) and Weinreb α-(BTFPsulfonyl)-acetamide (5) have successfully been employed in the Julia-Kocienski olefination of aldehydes with K2CO3 as the base at 120°C in DMF under solid/liquid phase-transfer catalysis conditions to afford α,β- unsaturated esters and Weinreb amides, respectively. The corresponding products were obtained in good yields and with high E stereoselectivities (E/Z up to >99:1), especially in the case of the amides. A detailed computational study of the Julia-Kocienski olefination with BTFP sulfone 4 was carried out and confirmed the existence of an equilibrium in the initial addition of the sulfone enolate to the aldehyde and, in contrast to other proposed mechanisms, a non-concerted final elimination of SO2 and 3,5-bis-(trifluoromethyl) phenoxide. A plausible explanation for the high E diastereoselectivity observed in the reaction has been suggested based on kinetic considerations at spirocyclic TS2 and thermodynamic factors during the elimination after TS2. ESI-MS studies carried out during the olefination reaction of benzaldehyde with BTFP sulfone 4 were used to characterize the sulfone enolate and the intermediate assumed for the reaction mechanism. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Highly (E)-selective wadsworth-emmons reactions promoted by methylmagnesium bromide
Claridge, Timothy D. W.,Davies, Stephen G.,Lee, James A.,Nicholson, Rebecca L.,Roberts, Paul M.,Russell, Angela J.,Smith, Andrew D.,Toms, Steven M.
supporting information; experimental part, p. 5437 - 5440 (2009/06/18)
(Chemical Equation Presented) An experimentally simple protocol for the very highly (E)-selective Wadsworth-Emmons reaction [(E):(Z) selectivities in excess of 180:1 in some cases] of a range of straight-chain and branched aliphatic, substituted aromatic, and base-sensitive aldehydes via reaction with an alkyl diethylphosphonoacetate and MeMgBr is reported.
Peterson Olefination Reaction Using (Trimethylgermyl)acetate. Stereoselective Synthesis of (E)-2-Alkenoic Acid Esters
Inoue, Sumie,Sato, Yoshiro
, p. 347 - 352 (2007/10/02)
Peterson-type reaction of (trimethylgermyl)acetates 1 with aldehydes and ketones 2 gave stereoselectively (E)-2-alkenoic acid esters (E)-4 after stirring at -78 deg C and warming to room temperature.High yields of the reaction intermediates threo- and erythro-3-hydroxy-2-(trimethylgermyl)alkanoic acid esters 3 were obtained when the reaction was quenched at -78 deg C.The paths for conversion of threo-3 and erythro-3 to (E)-4 are discussed.
