112489-57-3Relevant academic research and scientific papers
Regio- And stereoselective synthesis of alkyl allylic ethers via gold(l)-catalyzed intermodular hydroalkoxylation of allenes with alcohols
Zhang, Zhibin,Widenhoefer, Ross A.
supporting information; scheme or table, p. 2079 - 2081 (2009/04/10)
Reaction of 1-phenyl-1,2-butadiene with 2-phenyl-1-ethanol catalyzed by a 1:1 mixture of a gold(l) W-heterocyclic carbene complex and AgOTf at room temperature for 1 h led to isolation of (E)-(3-phenethoxy-1-butenyl)benzene in 96% yield as a single regio-
Improved E-selectivity in the Wittig reaction of stabilized ylides with alpha-alkoxyaldehydes and sugar lactols.
Harcken,Martin
, p. 3591 - 3593 (2007/10/03)
[reaction: see text]. The Wittig reactions of alpha-alkoxyaldehydes and sugar lactols with stabilized ylides such as (alkoxycarbonylmethylene)triphenylphosphoranes typically proceed with low E-selectivities. However, we have discovered that the reaction o
"Chirality transfer" in iron-mediated dienylic substitutions via highly enantiomerically enriched planar chiral 1-phenylsulfonyl-substituted tricarbonyl(η5-pentadienyl)iron(1 +) complexes
Enders, Dieter,Jandeleit, Bernd,Von Berg, Stefan
, p. 219 - 236 (2007/10/03)
The preparation of highly diastereo-and enantiomerically enriched planar chiral 1-phenylsulfonyl-substituted tricarbonyl(η5-pentadienyl)iron(1 +) complexes 7 [syn,syn-(1R,5R)-7 and syn,syn-(1S,5S)-7 (cisoid-or U-forms); de > 99% ≡ 5-syn-CH3/5-anti-CH3 ? 100:1, ee > 99%; 87% quant. from resolved 6] is described. Starting from the enantiopure diene (1E,3E,S)-5 both enantiomers of the cationic complexes syn,syn-7 become readily accessible via chromatographic resolution of the diastereomeric mixture of the corresponding neutral tricarbonyl(η4-diene)iron(0) complexes 6 [(1R,5S)-6 ≡ ψ-endo-6 and (1S,5S)-6 ≡ ψ-exo-6; de > 99%, ee > 99%; 85% quant. prior to resolution]. The nucleophilic addition of hetero and carbon atom nucleophiles (morpholine, silyl enol ether 8 and silyl ketene acetal 9) to the racemic complex syn,syn-(1R/S,5R/S)-7 afforded the neutral ε-substituted tricarbonyl(η4-diene)iron(0) complexes rac-ψ-exo-10a-c in moderate yields [43-68% from syn,syn-(1R/S,5R/S)-7] as single geometrical isomers [(E,Z) or (E,E); kinetic (U-form/strong nucleophile) or thermodynamic (S-form/less reactive nucleophile) control]. Likewise, nucleophilic addition to the stereochemically homogeneous complexes syn,syn-(1R,5R)-7 or syn,syn-(1S,5S)-7 followed by oxidative cleavage of the carbonyliron fragment offers an access to ε-substituted dienes 11a-c in moderate to fair yields [45-65%, (E,Z)/(E,E) = > 85:1-1:3] with enantiomeric excesses ranging from > 99%/98.9% [(1E,3Z,R)-11a/(1E,3Z,S)-11a] to 93% [(6E,8E,S)-11b]. The stereochemistry of the formation and the stereochemical pathways of the nucleophilic addition reactions of the nonracemic complexes syn,syn-7 leading to the dienes 11a-c as well as spectroscopic and structural details are discussed. Furthermore, the reaction proceeds with virtually complete "chirality transfer" from C-O via C-Fe to C-N or C-C, respectively, with either retention or inversion of stereochemistry of the stereogenic centre with respect to the starting material (S)-1 depending strongly on the reaction conditions. The observed ε-regioselectivity of the nucleophilic addition reaction displays the synthetic equivalence of the cationic complexes of type syn,syn-7 with a planar chiral a6-synthon allowing an umpolung of the classical d6-chemistry.
Diastereoselectivity of the thio-Claisen rearrangement of acyclic precursors bearing a chiral centre adjacent to carbon 6
Desert, Stephane,Metzner, Patrick
, p. 10327 - 10338 (2007/10/02)
A number of chiral allylic alcohols have been prepared and submitted to a Mitsunobu reaction with dithioacetic acid. Allyl dithioesters were deprotonated by LDA at -30°C and resulting enethiolates were quenched with iodomethane to afford quantitatively S-
1,3-dipolar cycloaddition reactions of azomethine ylides on enantiomerically pure (E)-γ-alkoxy-α,β-unsaturated esters
Annunziata,Cinquini,Cozzi,Raimondi,Pilati
, p. 1329 - 1342 (2007/10/02)
Enantiomerically pure (E)-γ-alkoxy-α,β-unsaturated esters were reacted with azomethine ylides obtained from glycine imines in the presence of LiBr and diazabicyloundecene (DBU), to afford tetrasubstituted pyrrolidines with complete regiocontrol and fair to excellent diastereoselectivity (only two diastereoisomers formed in up to 96: 4 diastereoisomeric ratio). The results are compared with those of other 1,3-dipolar cycloadditions, and the origin of stereocontrol is discussed.
AN OBSERVATION OF DIASTEREOFACE SELECTIVITY IN THERMAL REACTIONS BETWEEN δ-ALKOXYALLYLSTANNANES AND ALDEHYDES
Mortlock, Simon V.,Thomas, Eric J.
, p. 2479 - 2482 (2007/10/02)
The δ-alkoxyallylstannanes (4) and (5) react stereoselectively on heating with p-nitrobenzaldehyde to provide the homoallylic alcohols (14) - (17), with (14) : (15) = 82 : 18; (16) : (17) = 73 : 27
CATALYTIC OSMYLATION OF ELECTRON POOR ALLYLIC ALCOHOLS AND ETHERS. A SYNTHETIC APPROACH TO BRANCHED CHAIN SUGARS
Bernardi, Anna,Cardani, Silvia,Scolastico, Carlo,Villa, Roberto
, p. 491 - 502 (2007/10/02)
The catalytic osmylation of electron-poor allylic ethers and alcohols was studied.In the case of γ-alkoxy E-enoates reaction selectivity was found to range from 2:1 to 8:1 in favor of the arabino (2,3-syn - 3,4-anti) product, regardless of the double bond
THE REACTION OF CARBOHYDRATE-DERIVED ALKOXYALDEHYDES WITH METHOXYCARBONYLMETHYLENETRIPHENYLPHOSPHORANE: STEREOSELECTIVE SYNTHESIS OF β-UNSATURATED ESTERS
Valverde, Serafin,Martin-Lomas, Manuel,Herradon, Bernardo,Garcia-Ochoa, Silvestre
, p. 1895 - 1902 (2007/10/02)
The reaction of several carbohydrate-derived alkoxyaldehydes with methoxycarbonylmethylenetriphenylphosphorane affords α,β-unsaturated esters with Z-stereoselectivity.The stereoselectivity depends on the substrate structure and the nature of the solvent u
INTRAMOLECULAR NITRILE OXIDE CYCLOADDITION ON CHIRAL OLEFINS : A STEREOCONTROLLED APPROACH TO β-KETOL PRECURSORS.
Annunziata, Rita,Cinquini, Mauro,Cozzi, Franco,Dondio, Gulio,Raimondi, Laura
, p. 2369 - 2380 (2007/10/02)
The intramolecular nitrile oxide cycloaddition reaction on (E) or (Z) olefins featuring a sulphur atom along the carbon chain connecting dipole and dipolarophile occurs with a poor to excellent anti stereoselectivity, which is mainly affected by the subst
