540485-26-5Relevant academic research and scientific papers
Enantioselective Hydrosilylation of Imines Catalyzed by Chiral Zinc Acetate Complexes
Bez?ada, Agata,Szewczyk, Marcin,Mlynarski, Jacek
, p. 336 - 342 (2016/01/15)
A series of zinc acetate complexes with optically pure diphenylethanediamine (DPEDA)-derived ligands have been employed as enantioselective catalyst for the hydrosilylation of various imines. High control of stereoselectivity (up to 97% ee) and excellent yields (up to 96%) were gained for a broad range of N-phosphinoylimines by using (R,R)-N,N′-dibenzyl-1,2-diphenylethane-1,2-diamine. This is the first successful application of an air-stable and environmentally friendly chiral Zn(OAc)2 complex instead of the previously used harmful diethylzinc in the asymmetric reduction of the C=N double bond.
Synthesis of Air- and Moisture-Stable, Storable Chiral Oxorhenium Complexes and Their Application as Catalysts for the Enantioselective Imine Reduction
Das, Braja Gopal,Nallagonda, Rajender,Dey, Dhananjay,Ghorai, Prasanta
supporting information, p. 12601 - 12605 (2015/09/01)
Air-/moisture-stable, crystalline, and storable chiral salicyloxazoline based oxorhenium(V) complexes have been synthesized and their catalytic application for the asymmetric reduction of ketimines using hydrosilane as hydride source is disclosed. A broad substrate scope, high yields, and excellent enantioselectivities (up to 99 %) are attained. Furthermore, the syntheses of enantiopure α-amino esters, γ- and δ-lactams, and isoindolinones have also been carried out using this methodology. Finally, the method has been applied to synthetic targets of pharmaceutical relevance, such as R-(+)-salsolidine and R-(+)-crispine A.
Direct catalytic enantio- and diastereoselective Mannich reaction of isocyanoacetates and ketimines
Ortin, Irene,Dixon, Darren J.
supporting information, p. 3462 - 3465 (2014/04/03)
A catalytic asymmetric synthesis of imidazolines with a fully substituted β-carbon atom by a Mannich-type addition/cyclization reaction of isocyanoacetate pronucleophiles and N-diphenylphosphinoyl ketimines has been developed. When a combination of a cinchona-derived aminophosphine precatalyst and silver oxide was employed as a binary catalyst system, good reactivity, high diastereoselectivities (up to 99:1 d.r.), and excellent enantioselectivities (up to 99 % ee) were obtained for a range of substrates. Binary catalyst system: A catalytic asymmetric synthesis of imidazolines with a fully substituted β-carbon atom through a Mannich-type addition/cyclization reaction of isocyanoacetate pronucleophiles and N-diphenylphosphinoyl ketimines has been developed. By employing a cinchona-derived aminophosphine precatalyst and silver oxide as a binary catalyst system, good reactivity and high diastereo- and enantioselectivities were obtained.
Creation through immobilization: A new family of high performance heterogeneous bifunctional iminophosphorane (BIMP) superbase organocatalysts
Goldys, Anna M.,Nez, Marta G.,Dixon, Darren J.
supporting information, p. 6294 - 6297 (2015/02/05)
An immobilized chiral bifunctional iminophosphorane superbase organocatalyst has been developed and applied in a range of challenging enantioselective reactions. A unique feature of this novel catalytic system is that the final step creation of the iminophosphorane occurs at the point of immobilization. The utility of the immobilized catalyst system was demonstrated in the nitro-Mannich reaction of ketimines as well as the conjugate addition of high pKa 1,3-dicarbonyl pro-nucleophiles to nitrostyrene. Catalyst recycling was also demonstrated.
Asymmetric transfer hydrogenation of ketimines using well-defined iron(II)-based precatalysts containing a PNNP ligand
Mikhailine, Alexandre A.,Maishan, Mazharul I.,Morris, Robert H.
supporting information, p. 4638 - 4641 (2012/10/29)
Well-defined iron(II)-based complexes containing PNNP ligands catalyze a highly enantioselective reduction of N-(diphenylphosphinoyl)- and N-(p-tolylsulphonyl)-ketimines. Under mild conditions and low catalyst loading, the ketimines are successfully reduced to the corresponding amines in enantiomeric excess ranging from 94 to 99%.
Facile and efficient enantioselective strecker reaction of ketimines by chiral sodium phosphate
Shen, Ke,Liu, Xiaohua,Cai, Yunfei,Lin, Lili,Feng, Xiaoming
supporting information; experimental part, p. 6008 - 6014 (2010/02/28)
A facile and efficient enantioselective Strecker reaction of ketimines catalyzed by a chiral alkali-metal salt has been developed. When 10 mol% BNPNa (BNP=1,1'-binaphthyl-2,2'-diylphosphate) prepared in situ and 10 mol% para-tert-butylortho-adamantylphenol (PBAP) were introduced into the reaction, up to 96% yield and up to 95% ee (ee=enantiomeric excess) were obtained. Both aliphatic and aromatic ketimines, especially sterically bulky cyclic ketimines derived from β-acetonaphthone, α-indanone, and α-tetralone were found suitable for this reaction. On the basis of the experimental results and previous reports, trimethylsilyl cyanide (TMSCN) was indicated to be the real reactive nucleophile despite the existence of PBAP, and a possible working model was proposed to explain the origin of the asymmetric induction. The facile availability of 1,1'-binaphthyl-2,2'-diylphosphoric acid (BNPH) and the simplicity of the procedure are beneficial for practical applications.
Enantioselective Strecker reaction of phosphinoyl ketoimines catalyzed by in situ prepared chiral N,N′-dioxides
Huang, Jinglun,Liu, Xiaohua,Wen, Yuehong,Qin, Bo,Feng, Xiaoming
, p. 204 - 208 (2007/10/03)
The enantioselective Strecker reaction of N-diphenylphosphinoyl ketoimines has been achieved by use of in situ prepared chiral N,N′-dioxide catalyst from L-piperidinamide 3f and m-chloroperoxybenzoic acid (m-CPBA). Excellent yields (up to 99%) and high enantioselectivities (up to 92% ee) were obtained. In particular, in situ prepared catalyst with readily available chiral material made the procedure more convenient. Moreover, the L-piperidinamide 3f-derived N,N′-dioxide 9 could be recycled and reused at least five times without any loss of either catalytic activity or enantioselectivity.
Catalytic enantioselective Strecker reaction of ketoimines
Masumoto, Shuji,Usuda, Hiroyuki,Suzuki, Masato,Kanai, Motomu,Shibasaki, Masakatsu
, p. 5634 - 5635 (2007/10/03)
A new method for the catalytic enantioselective Strecker reaction (cyanation) of N-diphenylphosphinoyl ketoimines is described. The asymmetric catalyst is a chiral gadolinium complex prepared from Gd(OiPr)3 and the d-glucose-derived ligand 3 in a 1:2 ratio. The reaction has a broad substrate generality, giving high enantioselectivity from aromatic, ethyl, primary alkyl, and α,β-unsaturated ketoimines. The products could be easily converted to disubstituted α-amino acids and their derivatives. Copyright
