1400149-69-0Relevant articles and documents
Novel chiral sulfinamide phosphines: Valuable precursors to chiral β-aminophosphines
Chen, Peng,Su, Xiao,Zhou, Wei,Xiao, Yuanjing,Zhang, Junliang
, p. 2700 - 2706 (2016/05/10)
Starting from commercially available aldehyde and chiral tert-butanesulfinamide, a series of chiral sulfinamide phosphines (Xiao-Phos) were synthesized via a two-step condensation-nucleophilic addition procedure. In most cases, nucleophilic addition of th
Tunable Bifunctional Phosphine-Squaramide Promoted Morita-Baylis-Hillman Reaction of N-Alkyl Isatins with Acrylates
Dong, Ze,Yan, Chao,Gao, Yongzhi,Dong, Chune,Qiu, Guofu,Zhou, Hai-Bing
, p. 2132 - 2142 (2015/06/23)
A series of highly tunable bifunctional phosphine-squaramide H-bond donor organocatalysts 6 has been synthesized from inexpensive and commercially available β-amino alcohols in moderate yields. Catalyst 6 can efficiently promote the asymmetric Morita-Baylis-Hillman (MBH) reaction of N-alkyl isatins with acrylate esters providing the chiral 3-substituted 3-hydroxy-2-oxindoles in good yields and enantioselectivities (up to 93 yield and 95 ee), in which the challenging substrate tert-butyl acrylate 9d, provided the best ee value to date. Moreover, this methodology was applied successfully in the synthesis of chiral cyclic spiropyrrolizidineoxindole and γ-butyrolactone derivatives without enantioselectivity deterioration. The possible mechanism of this MBH reaction was also investigated by 31PNMR, ESI-MS and KIE studies. The KIE experiments show that the electrophilic addition of N-methyl isatin to the complex of acrylate ester and phophine-squaramide is the rate-determing step of the asymmetric MBH reaction.
Synthesis of iron P-N-P' and P-NH-P asymmetric hydrogenation catalysts
Sonnenberg, Jessica F.,Lough, Alan J.,Morris, Robert H.
, p. 6452 - 6465 (2015/02/19)
Complexes of the type mer,trans-[Fe(P-N-P)(CO)2Br]BF4 are known to be precatalysts for the asymmetric direct hydrogenation of ketones and imines. Employing related ligand scaffolds, we successfully generated and tested the series of three new precatalysts [Fe(PCy2CH2CH-NCH(R)CH2PPh2)(CO)2Br]BF4 with chirality derived from (S)-amino alcohols with phenyl, benzyl, and isopropyl substituents (R), yielding fairly active and selective systems. For the reduction of acetophenone to (S)-1-phenylethanol turnover frequencies up to 920 h-1 and up to 74% enantiomeric excess at 50 °C and 5-25 atm of H2 were obtained. We found, however, that placing these large groups R next to nitrogen was found to be deleterious to catalytic activity. Extending the scope of the ligand structure, we then developed a series of six P-N-P and five P-NH-P systems starting with o-diphenylphosphinobenzaldehyde and the phosphine-amines PPh2CHR1CHR2NH2 (R1 = H, Ph, CH2Ph, iPr with R2 = H or R1 = Me, Ph with R2 = Ph) as well as their corresponding [Fe(P-N-P)(NCMe)3][BF4]2 and [Fe(P-NH-P)(NCMe)3][BF4]2 complexes, which were not catalytically active. Finally, we made the new achiral iron complex mer,cis-Fe(PPh2(o-C6H4)CHNCH2CH2PPh2)(CO)Br2, which was active for the direct hydrogenation of acetophenone, achieving turnover frequencies of 800 h-1 at 50°C and 25 atm of H2.
Enantioselective copper-catalyzed 1,4-addition of dialkylzincs to enones followed by trapping with allyl iodide derivatives
Kawamura, Kenjiro,Fukuzawa, Hitomi,Hayashi, Masahiko
, p. 640 - 647 (2011/08/06)
Enantioselective copper-catalyzed 1,4-addition of dialkylzincs to enones proceeded in the presence of 0.1 mol% of Cu(OTf)2 and 0.25 mol% of an N,N,P-ligand containing a quinoline moiety to afford the corresponding conjugated adducts in 99%ee. The intermediate zinc enolates were trapped with substituted allyl iodides to give disubstituted ketones with high diastereoselectivity and enantioselectivity.
The enantioselective intramolecular Morita-Baylis-Hillman reaction catalyzed by amino acid-derived phosphinothiourea
Gong, Jing-Jing,Yuan, Kui,Song, Hong-Liang,Wu, Xin-Yan
experimental part, p. 2439 - 2443 (2010/06/12)
A series of chiral bifunctional phosphinothioureas derived from l-amino acids have been developed to promote the enantioselective intramolecular Morita-Baylis-Hillman reaction. The process afforded the cyclic hydroxyl enones with up to 84% ee and good yields under mild conditions.
Synthesis of chiral aminophosphines from chiral aminoalcohols via cyclic sulfamidates
Guo, Rongwei,Lu, Shuiming,Chen, Xuanhua,Tsang, Chi-Wing,Jia, Wenli,Sui-Seng, Christine,Amoroso, Dino,Abdur-Rashid, Kamaluddin
supporting information; experimental part, p. 937 - 940 (2010/05/02)
(Chemical Equation Presented) Protic aminophosphines with multiple chiral centers were synthesized in good yields and high purity by the nucleophilic ring-opening of N-protected cyclic sulfamidates with metal phosphides, followed by hydrolysis and deprote
Novel N,N,P-tridentate ligands for the highly enantioselective copper-catalyzed 1,4-addition of dialkylzincs to enones
Kawamura, Kenjiro,Fukuzawa, Hitomi,Hayashi, Masahiko
supporting information; experimental part, p. 3509 - 3512 (2009/05/07)
(Chemical Equation Presented) Use of 0.25 mol % of the N,N,P-tridentate ligand containing the 2-quinolyl moiety (1 and 2) and 0.1 mol % of Cu(OTf) 2 enabled the enantioselective 1,4-addition of dialkylzincs to cyclic enones to produce 1,4-adduc
Investigation of the importance of nitrogen substituents in a N-P chiral ligand for enantioselective allylic alkylation
Anderson, James C.,Cubbon, Rachel J.,Harling, John D.
, p. 923 - 935 (2007/10/03)
The synthesis of three chiral chelate nitrogen-phosphorus (S)-valine derived ligands with the potential for stereogenic nitrogen donation is described. In palladium catalysed allylic substitution reactions the ligands induced varying enantioselectivities ranging from 92% e.e. of the (R)-enantiomer to 83% e.e. of the (S)-enantiomer. Structural and spectroscopic investigations into the origin of this effect were conducted, but were inconclusive. However, the importance of the consideration of N-substituents in such systems is highlighted.
Synthesis of heterofunctionalized multidentate diphosphines
Quirmbach, Michael,Holz, Jens,Tararov, Vitali I.,B?rner, Armin
, p. 775 - 780 (2007/10/03)
The synthesis of new chiral multidentate amino- and amidophosphine ligands bearing up to six potential coordination sites were synthesized starting from L-valine. Based on these compounds chiral Ru(II) complexes were prepared, characterized and tested in the asymmetric transfer hydrogenation of aryl-alkyl ketones. In all cases investigated the catalyst bearing additional hydroxy groups gave lower conversions than the complex without hydroxy groups. Highest enantioselectivity was achieved with isobutyrophenone as substrate (69%ee). (C) 2000 Elsevier Science Ltd.
A new class of C2-symmetric diphosphine ligands derived from valine: Remarkably diverse behavior in catalytic asymmetric transformations
Saitoh, Akihito,Uda, Takashi,Morimoto, Toshiaki
, p. 4501 - 4511 (2007/10/03)
A new C2-symmetric diphosphine ligand 8a was readily prepared in one step by treatment of the synthetic precursor of VALAP, 7, with phthaloyl chloride. Remarkably high levels of asymmetric induction, over 99% ee, were achieved using 8a in palladium-catalyzed asymmetric allylic transformations of sterically less demanding cyclohexenyl substrates 9. The ligand system was easily extended to the development of analogous chiral auxiliaries 8b,c by the identical procedure but using isophthaloyl chloride and succinyl chloride. However, the ligands 8b,c exhibited much lower catalytic activity. In contrast to the asymmetric allylic substitutions, 8c demonstrated significant improvement of enantioselectivity, up to 64% ee, in rhodium- catalyzed asymmetric hydrosilylations of acetophenone 11a compared to 35% ee using 8a. In this way, the versatility of the present ligand system played an important role in variations of substrates and reaction types. (C) 1999 Elsevier Science Ltd.
