89996-92-9Relevant academic research and scientific papers
Intrazeolite photooxygenation of chiral alkenes. Control of facial selectivity by confinement and cation-π interactions
Stratakis, Manolis,Raptis, Christos,Sofikiti, Nikoletta,Tsangarakis, Constantinos,Kosmas, Giannis,Zaravinos, Ioannis-Panagiotis,Kalaitzakis, Dimitris,Stavroulakis, Dimitris,Baskakis, Constantinos,Stathoulopoulou, Aggeliki
, p. 10623 - 10632 (2006)
Depending on the nature of the substituents on the stereogenic carbon atom, the ene reaction of singlet oxygen with several chiral alkenes by confinement within thionin-supported zeolite NaY, may exhibit significant changes on facial selectivity by comparison to their photooxygenation reaction in solution. It is proposed that, apart from the conformational consequences as a result of the alkene confinement within the zeolite cavities, a synergism between Na+-π interactions and singlet oxygen-Na+ interactions plays a significant role in the transition states of ene hydroperoxidation. Within NaY, the diastereoselectivity may significantly depend on the site selectivity, as probed through specific deuterium labelling of trisubstituted alkenes bearing a gem-dimethyl group. In certain cases, a remote stereogenic centre relative to the reacting double bond may induce enhanced diastereoselection and regioselectivity.
Carbonyl olefination with α-stannyl ester enolates: a new synthesis of α,β-unsaturated esters
Zapata, Antonio,Nunez, Beatriz M.,Ferrer, Fernando J.
, p. C9 - C11 (2007/10/02)
The reaction of α-stannyl ester enolates with carbonyl compounds is described. α,β-Unsaturated esters are obtained in good yields.A reaction mechanism is proposed.
SYNTHESE STEREOSELECTIVE D'ESTERS α,β-ETHYLENIQUES α-METHYLES Z OU E PAR LA REACTION DE WITTIG-HORNER A PARTIR DE PHOSPHONATES OU D'OXYDES DE PHOSPHINE
Etemad-Moghadam, Guita,Seyden-Penne, Jacqueline
, p. 5153 - 5166 (2007/10/02)
The reaction of α-branched aldehydes with diethyl 1-carbomethoxyethyl phosphonate 1b in THF/nBuLi at low temperature leads stereoselectively to Z α-methyl α,β-unsaturated esters.From a linear aldehyde, the reaction is less stereoselective, while from α,β-unsaturated ones, the E isomers are predominantly formed in good yields.From diphenyl 1-carbomethoxyethyl phosphine oxide 2b, E α-methyl α,β-unsaturated esters are stereoselectively formed either in DMF/tBuOK or in phase transfer conditions, whatever the starting aldehyde is, also in good yields.This reagent can thus advantageously replace the corresponding P-ylid.In all cases, the reaction conditions are determined so that by-products formation is minimized.
NOUVEAUX REACTIFS PRECURSEURS D' OLEFINES TRISUBSTITUEES E : LES OXYDES DE PHOSPHINE.
Seyden-Penne, J.,Etemad-Moghadam, G.,Bottin-Strzalko, T.,Simonnin, M.-P.
, p. 179 - 182 (2007/10/02)
From NMR data, phosphine oxides 4 show similarity to Pylids and give E trisubstituted olefins from saturated and unsaturated aldehydes.
