720701-50-8Relevant academic research and scientific papers
Preparative-Scale Synthesis of Vedejs Chiral DMAP Catalysts
Kinens, Artis,Balkaitis, Simonas,Suna, Edgars
, p. 12449 - 12459 (2018)
A scalable synthesis of chiral Vedejs-type DMAP catalysts is reported. The key step of the synthesis is amination of the enantiomerically pure 4-chloropyridine derivative using well-defined ZnCl2(amine)2 complexes. A series of Zn(II)-amine complexes have been synthesized to explore the scope of the ZnCl2-mediated amination of 4-halopyridines. Mechanistic studies support a Zn(II)-facilitated nucleophilic aromatic substitution as a plausible mechanism for the chlorine-to-amine exchange.
New atropisomeric biaryl derivatives of 4-aminopyridine - Identification of an improved nucleophilic catalyst for asymmetric acylation of sec-alcohols
Spivey, Alan C.,Leese, David P.,Zhu, Fujiang,Davey, Stephen G.,Jarvest, Richard L.
, p. 4513 - 4525 (2007/10/03)
The synthesis, CSP-HPLC resolution, and absolute configuration assignment of a series of 4-dialkylaminopyridine-based atropisomeric biaryls are described. Screening of these enantiomerically pure catalysts, which differ only in the nature of the 4-dialkylamino substituent, for the kinetic resolution of 1-(1-naphthyl)ethanol reveals the importance of this group on the selectivity of catalysis. The di-n-butylamino derivative displays the most favourable catalytic profile. The utility of this catalyst for the kinetic resolution of a selection of sec-alcohols, including a precursor for the synthesis of the antidepressant fluoxetine hydrochloride (Prozac) are reported. The possible role of the dialkylamino group in chirality transfer is discussed.
Energy barriers to rotation in axially chiral analogues of 4-(dimethylamino)pyridine
Spivey,Charbonneau,Fekner,Hochmuth,Maddaford,Malardier-Jugroot,Redgrave,Whitehead
, p. 7394 - 7401 (2007/10/03)
The barriers to enantiomerization of a series of axially chiral biaryl analogues of 4-(dimethylamino)-pyridine (DMAP) 1-10 were determined experimentally by means of dynamic HPLC measurements and racemization studies. The barriers to rotation in derivatives 1-6 (based on the bicyclic 5-azaindoline core) were lower than those in the corresponding derivatives 7-10 (based on the monocyclic DMAP core). Semiempirical (PM3), ab initio Hartree-Fock (HF/STO-3G), and density functional theory (DFT/B3LYP/6-31G*) calculations reveal that these differences in barriers to rotation are the result of differing degrees of hybridization of the non-pyridyl nitrogen in the enantiomerization transition states (TSs). The importance of heteroatom hybridization as a factor in determining nonsteric contributions to barriers to rotation in azabiaryls of this type is discussed.
