80868-49-1Relevant academic research and scientific papers
Mixed-Ligand Arenechromium Carbonyl Complexes as Electronic Modulators
Jones, Graham B.,Chapman, Brant J.,Mathews, Jude E.
, p. 2928 - 2938 (1998)
A number of mixed ligand η6 arenechromium carbonyl complexes have been prepared and investigated for their ability to effect electronic modulation of arene chemistry. In the case of an aniline-derived system, the arenechromium carbonyl complex is able to modulate the inductive capacity of the aniline nitrogen atom and thus, regulate its anchimeric ability. In the case of 8-phenylmenthol and benzyloxazolidinone derivatives, modulation of arene π basicity is achieved, and results suggest that important vinylarene π-π interactions exist in acrylate derivatives of these chiral auxiliary systems.
AlPO4-Catalysed Asymmetric Diels-Alder Reactions of Cyclopentadiene with Chiral Acrylates
Cativiela, Carlos,Fraile, Jose M.,Garcia, Jose I.,Mayoral, Jose A.,Campelo, Juan M.,et al.
, p. 2507 - 2512 (2007/10/02)
Reactions of cyclopentadiene with several chiral acrylates are studied and compared with the same reactions catalysed by Zn(II)-exchanged K10 montmorillonite.In general, amorphous AlPO4 is a more efficient catalyst than the clay.In particular, the reaction of cyclopentadiene with (-)-8-phenylmenthyl acrylate leads to 74percent diastereomeric excess (d.e.) in methylene chloride at low temperatures.This result constitutes the highest asymmetric induction described to date for solid-catalysed asymmetric Diels-Alder reaction.When the reactions are carried out in the absence of a solvent a noticeable decrease in selectivity is observed, probably due to an extensive competition of non-catalysed reaction.
Fluorinated alcohols as solvents for Diels-Alder reactions of chiral acrylates
Cativiela,Garcia,Mayoral,Royo,Salvatella
, p. 1613 - 1618 (2007/10/02)
Fluorinated alcohols increase the rates of endo/exo selectivities of the Diels-Alder reactions of cyclopentadiene with (-)-menthyl and (-)-8-phenylmenthyl acrylates. The use of fluorinated alcohols also increases the diastereofacial selectivity in the reactions of (-)-menthyl acrylate, but decreases it when the dienophile is (-)-8-phenylmenthyl acrylate. These facts are accounted for by the conformational preferences of the dienophile in non-HBD solvents and by the tendency of fluorinated alcohols to shift the conformational equilibrium towards the s-trans conformation.
Asymmetric syntheses with a new optically active perhydronaphthalene based chiral auxiliary
Hamon,Holman,Massy-Westropp
, p. 9593 - 9604 (2007/10/02)
(1R,4aS,8S,8aS)-8-(5'-Methoxy-2'-methylphenyl)-8-methyldecahydro-1-nap hthalenol 3a is a highly efficient chiral auxiliary in the Diels-Alder addition of its acrylate ester 5 and in the DIBAL-H and Grignard reactions of its phenylglyoxylate ester 7.
A REINVESTIGATION OF ASYMMETRIC INDUCTION IN DIELS-ALDER REACTIONS
Oppolzer, Wolfgang,Kurth, Mark,Reichlin, Daniel,Moffatt, Frank
, p. 2545 - 2548 (2007/10/02)
The chiral induction in the Diels-Alder addition 12, assessed reliably by (19)F-NMR-spectroscopy of the endo-esters 4, varied between 47-93 percent in favor of the 2-(R)-adducts 2 depending on the auxiliary chiral group and the Lewis-acid catalyst.
