698378-82-4Relevant academic research and scientific papers
Enantioselective synthesis of angularly substituted 1-azabicylic rings: Coupled dynamic kinetic epimerization and chirality transfer
Aron, Zachary D.,Ito, Tatsuya,May, Tricia L.,Overman, Larry E.,Wang, Jocelyn
, p. 9929 - 9948 (2013/10/22)
A new strategy for enantioselective synthesis of azacyclic molecules in which dynamic kinetic equilibration of diastereomeric iminium ions precedes a stereochemistry-determining sigmatropic rearrangement is reported. The method is illustrated by the synthesis, in high enantiomeric purity (generally 95-99% ee), of a variety of 1-azabicyclic molecules containing angular allyl or 3-substituted 2-propenyl side chains adjacent to nitrogen and up to three stereogenic centers. In these products, the size of the carbocyclic ring is varied widely (5-12 membered); however, useful yields are obtained in forming 1-azabicyclic products containing only fused pyrrolidine and piperidine rings. Chirality transfer from substituents at carbons 1 and 2 of the 3-butenylamine fragment of the starting material is investigated, with methyl and phenyl substituents at the allylic position shown to provide exquisite stereocontrol (generally 98-99% chirality transfer). An attractive feature of the method is the ability to carry out the key transformation in the absence of solvent. Illustrated also is the high yielding conversion of four such products to a new family of bicyclic β-amino acids of high enantiomeric purity.
Synthesis of enantiopure 1-aryl-1-butylamines and 1-aryl-3-butenylamines by diastereoselective addition of allylzinc bromide to imines derived from (R)-phenylglycine amide
Dalmolen, Jan,Van Der Sluis, Marcel,Nieuwenhuijzen, Jose W.,Meetsma, Auke,De Lange, Ben,Kaptein, Bernard,Kellogg, Richard M.,Broxterman, Quirinus B.
, p. 1544 - 1557 (2007/10/03)
The synthesis of enantiopure 1-aryl-1-butylamines via a highly diastereoselective addition of allylzinc bromide to imines derived from (R)-phenylglycine amide is reported. These are synthesised by a three-step procedure, which involves: (a) formation of the chiral imines; (b) asymmetric addition of the allylzinc reagent; (c) removal of the chiral auxiliary by means of a reductive or non-reductive method. The reductive method provides 1-aryl-1-butylamines whereas the non-reductive method preserves the double bond to afford 1-aryl-3-butenylamines. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Enantioselective Synthesis of Chiral Homoallyl Alcohols and Homoallylamines by Nucleophilic Addition of an Allylboron Reagent Modified by a Polymer-Supported Chiral Ligand
Itsuno, Shinichi,Watanabe, Katsuhiro,El-Shehawy, Ashraf A.
, p. 89 - 94 (2007/10/03)
Crosslinked polymer-supported chiral N-sulfonylamino alcohols 5-8 have been prepared by suspension polymerization of enantiopure N-sulfonylamino alcohol monomers 1-4 with styrene and divinylbenzene. Polymer-supported chiral allylboron reagents were prepared from the polymeric chiral ligands. Enantioselective additions of the polymer-supported allylboron reagents to aldehydes and N-(trimethylsilyl)imines have been successfully carried out in the heterogeneous system. The corresponding optically active homoallyl alcohols and homoallylamines were obtained in high yields with high enantioselectivities (up to 95% ee) which are almost the same as those obtained from homogeneous analogues. The polymer-supported chiral ligands used were recovered easily and can be reused without any loss of activity.
