121506-74-9Relevant academic research and scientific papers
Arynes and Cyclic Alkynes as Synthetic Building Blocks for Stereodefined Quaternary Centers
Picazo, Elias,Anthony, Sarah M.,Giroud, Maude,Simon, Adam,Miller, Margeaux A.,Houk,Garg, Neil K.
supporting information, p. 7605 - 7610 (2018/05/15)
We report a facile method to synthesize stereodefined quaternary centers from reactions of arynes and related strained intermediates using β-ketoester-derived substrates. The conversion of β-ketoesters to chiral enamines is followed by reaction with in situ generated strained arynes or cyclic alkynes. Hydrolytic workup provides the arylated or alkenylated products in enantiomeric excesses as high as 96%. We also describe the one-pot conversion of a β-ketoester substrate to the corresponding enantioenriched α-arylated product. Computations show how chirality is transferred from the N-bound chiral auxiliary to the final products. These are the first theoretical studies of aryne trapping by chiral nucleophiles to set new stereocenters. Our approach provides a solution to the challenging problem of stereoselective β-ketoester arylation/alkenylation, with formation of a quaternary center.
Stereoselective process for a CCR3 antagonist
Yue, Tai-Yuen,McLeod, Douglas D.,Albertson, Kevin B.,Beck, Steven R.,Deerberg, Joerg,Fortunak, Joseph M.,Nugent, William A.,Radesca, Lilian A.,Tang, Liya,Xiang, Cathie Dong
, p. 262 - 271 (2012/12/22)
A convergent, multikilogram, stereoselective synthesis of 1 is described. A key fragment, (S)-3-(4-fluorobenzyl)piperidine (2) was synthesized from valerolactam in three steps using our recently discovered Ir-BDPP-catalyzed asymmetric hydrogenation. Anoth
Asymmetric synthesis of a new helix-forming β-amino acid: trans-4-aminopiperidine-3-carboxylic acid
Schinnerl, Marina,Murray, Justin K.,Langenhan, Joseph M.,Gellman, Samuel H.
, p. 721 - 726 (2007/10/03)
We report a synthesis of a protected derivative of trans-4aminopiperidine-3-carboxylic acid (APiC). The route provides either enantiomer. All intermediates are purified by crystallization, and large-scale preparation is therefore possible. An analogous ro
A versatile route to β-enamino esters by acylation of lithium enamines with diethyl carbonate or benzyl chloroformate
Bartoli, Giuseppe,Cimarelli, Cristina,Dalpozzo, Renato,Palmieri, Gianni
, p. 8613 - 8622 (2007/10/02)
A versatile route to β-enamino esters 1, using accessible starting materials, was developed. Lithiated enamines are allowed to react with diethyl carbonate or benzyl chloroformate with the formation of the β-enamino esters 1a or 1b. The reaction is rather general from a wide array of ketimines and aldimines. Products included cyclic β-enamino esters 1aa-ac, very useful for the synthesis of natural products.
Facile enantioselective synthesis of two new bicyclic chiral templates
Belfield,Seo
, p. 461 - 466 (2007/10/02)
Optically active bicyclic dienes, 4 and 5 have been enantioselectively prepared in three and four steps, respectively. Mixtures of predominantly either the R or S enantiomer were obtained via an asymmetric alkylation of a chiral enamine.
Asymmetric formation of quaternary centers through aza-annulation of chiral β-enamino esters with acrylate derivatives
Barta, Nancy S.,Brode, Adam,Stille, John R.
, p. 6201 - 6206 (2007/10/02)
The aza-annulation of β-enamino ester substrates with acrylate derivatives was used for the stereoselective formation of quaternary carbon centers. Tetrasubstituted secondary enamines, in which the enamine tautomer was stabilized through conjugation with
Synthesis of Optically Active Michael Adducts Via Chiral Enamines
Brunner, Henri,Kraus, Joerg,Lautenschlager, Hans-Juergen
, p. 1161 - 1168 (2007/10/02)
Chiral enamines, obtained by Schiff base condensation from 1,3-dicarbonyl compounds and (R)-(+)-1-phenylethylamine, were found to undergo diastereoselective Michael reactions with α,β-unsaturated carbonyl compounds.After removal of the chiral auxiliary (R
