719304-60-6Relevant articles and documents
Energy barriers to rotation in axially chiral analogues of 4-(dimethylamino)pyridine
Spivey,Charbonneau,Fekner,Hochmuth,Maddaford,Malardier-Jugroot,Redgrave,Whitehead
, p. 7394 - 7401 (2001)
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.
Preparative-Scale Synthesis of Vedejs Chiral DMAP Catalysts
Kinens, Artis,Balkaitis, Simonas,Suna, Edgars
, p. 12449 - 12459 (2018/10/20)
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.