144561-93-3Relevant academic research and scientific papers
Highly enantioselective iridium-catalyzed hydrogenation of α,β-unsaturated esters
Li, Jia-Qi,Quan, Xu,Andersson, Pher G.
, p. 10609 - 10616 (2012/11/07)
α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals. Asymmetric hydrogenation: A variety of α,β-unsaturated esters were hydrogenated with high enantioselectivities (see scheme). The hydrogenated products have been used in synthetic transformations as well as in formal total syntheses. Copyright
Synthesis and utility of the 3,3-dimethyl-5-substituted-2-pyrrolidinone 'Quat' chiral auxiliary
Davies, Stephen G.,Dixon, Darren J.,Doisneau, Gilles J.-M.,Prodger, Jeremy C.,Sanganee, Hitesh J.
, p. 647 - 658 (2007/10/03)
The synthesis and utility of the 3,3-dimethyl-5-substituted-2-pyrrolidinone 'Quat' chiral auxiliary in stereoselective enolate reactions of attached N-acyl side chains combined with the mild and non-racemising conditions required for the ultimate removal of the chiral side chain is described.
Asymmetric aldol and alkylation reactions mediated by the 'quat' chiral auxiliary (R)-(-)-5-methyl-3,3-dimethyl-2-pyrrolidinone
Davies,Doisneau,Prodger,Sanganee
, p. 2373 - 2376 (2007/10/02)
Enolates derived from the N-propionoyl derivative of the 'quat' chiral auxiliary (R)-(-)-5-methyl-3,3-dimethyl-2-pyrrolidinone undergo highly stereoselective aldol and alkylation reactions. Removal of the auxiliary has been demonstrated with LiOH, PhCH2OLi, MeOMgBr and LiAlH4 to generate respectively (2R,3R)-3-hydroxy-2-methyl-3-phenylpropionic acid in homochiral form, and with 96% e.e. (S)-2-methyl-3-phenylpropionic acid and derived methyl and benzyl esters and with >94% e.e. (S)-2-methyl-3-phenylpropanol.
Enantiospecific preparation of [(2R,6S)-endo]-5-aza-1,10,10-trimethyl-3-oxatricyclo[5.2.1.02,6)]de can-4-one by a nitrene-mediated route from [(1S]-endo]-(-)-borneol and its utility as a chiral auxiliary in some asymmetric transformations
Banks,Blake,Cadogan,Dawson,Gosney,Grant,Gaur,Hodgson,Knight,Smith,Stevenson
, p. 7979 - 8006 (2007/10/02)
Attempted chiral aziridination of styrene by addition of optically-active alkoxycarbonylnitrene 5 derived from [(1S)-endo]-(-)-bornyl p-nitrobenzenesulphonoxycarboxy 4 is reported. No measurable asymmetric induction is observed under the various conditions employed, but in the absence of alkene, a tricyclic oxazolidin-2-one 8 is formed to which preparatively simpler access can be gained by thermal decomposition of azidoformate 7, either in 1,1,2,2-tetrachloroethane (50%) or by spray pyrolysis (58%). The oxazolidin-2-one 8 is demonstrated to be a successful chiral auxiliary by contemporary standards in a variety of asymmetric transformations, including alkylation, acylation, and aldol reactions for which high levels of asymmetric induction are observed. Diethylaluminium chloride catalysed Diels-Alder reactions exhibit poorer selectivity except for the cinnamoyl derivative 23 which is stereospecific.
