177263-77-3Relevant academic research and scientific papers
The preparation of trans-2,5- dialkylpyrrolidinylbenzyldiphenylphosphines: New phosphinamine ligands for asymmetric catalysis
Cahill, John P.,Bohnen, Frank M.,Goddard, Richard,Krueger, Carl,Guiry, Patrick J.
, p. 3831 - 3839 (1998)
The preparation of new phosphinamine ligands 3a, 3b, possessing an enantiopure trans-2,5-dialkylpyrrolidinyl unit is described. Of the three synthetic approaches investigated, two proved successful with similar overall yields of 50-60%. One approach forms
Preparation, structure, and reactivity of thioxo and imino derivatives of the triolide (and pentolide) from (R)-3-hydroxybutanoic acid
Brunner,Kuhnle,Seebach
, p. 319 - 345 (1996)
Reaction of the triolide 1 from (R)-3-hydroxybutanoic acid with Lawesson's reagent 5 leads to the mono-, di-, and trithio derivatives 6-8 which can be isolated in pure form (20-40% yields), and which have crystal structures very similar to the parent triolide 1. Similarly, pentolide 3 is converted to mixtures of various thio derivatives, three of which are separated (10-12) by HPLC and fully characterized. The X-ray structures of the mono- and of one of the dithiopentolides (10, 12) differ remarkably from each other. Reduction of the thiotriolides 6-8 (NaBH4, R3SnH, Cl3SiH, Raney-Ni) gives 12-membered rings containing up to three ether groups (chiral crown ethers, 15, 17-19) in poor yields. The thiotriolides react spontaneously and in yields of up to 96% with ammonia, certain primary amines, and hydroxylamine to give imine and oxime derivatives with intact 12-membered-ring backbones (20, 22-24, 30). The rigid structure of all the derivatives of triolide 1 puts the C = O, C = S, and C = NR O-, S-, and N-atoms in juxtaposition (a feature reminiscent of the side chains in the iron-binder enterobactin). Imines containing PPh2 groups are prepared (30, 33, 35) from the thiotriolides and tested as chiral ligands for Pd(II)-catalyzed 1,3-diphenylallylations (→ 37, enantiomer ratio up to 77:23). The reactions described demonstrate that multiple reactions of the triolide 1 from (R)-3-hydroxybutanoic acid which proceed through tetrahedral intermediates are possible without ring opening - the skeleton is remarkably stable, and this might be exploited as a template for bringing up to three pendent substituents into close proximity to allow a study of their interactions and cooperative properties. Also, the di- and trithio derivatives 7 and 8 could be used for cross-linking in molecules containing primary NH2 groups.
HYDROGENATION OF CARBONYLS WITH TETRADENTATE PNNP LIGAND RUTHENIUM COMPLEXES
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Page/Page column 18; 20, (2019/10/04)
The present invention relates to catalytic hydrogenation processes, using Ru complexes with tetradentate ligands of formula L in hydrogenation processes for the reduction of ketone, aldehyde, ester or lactone into the corresponding alcohol or diol respectively. The described processes use a ruthenium complex of the formula (1) as defined below, and where the ligand (L) is defined by the Markush formula shown above.
Tridentate P,N,N-ligand promoted copper-catalyzed [3 + 2] cycloaddition of propargylic esters with β-enamino esters: Synthesis of highly functionalized pyrroles
Li, Qing,Hou, Chuan-Jin,Hui, Yun-Ze,Liu, Yan-Jun,Yang, Rui-Feng,Hu, Xiang-Ping
, p. 85879 - 85883 (2015/11/03)
A copper-catalyzed [3 + 2] cycloaddition of propargylic esters with β-enamino esters under mild reaction conditions for the construction of highly functionalized pyrroles has been developed. By employment of a newly developed tridentate P,N,N-ligand, a va
Direct asymmetric α-allylation of ketones with allylic alcohols Via Pd/enamine cooperative function
Yasuda, Shigeo,Kumagai, Naoya,Shibasaki, Masakatsu
, p. 745 - 757 (2013/08/15)
Direct asymmetric α-allylation of ketones with allylic alcohols is described. The combination of palladium with a new phosphine ligand bearing a chiral proline moiety promoted the reaction to afford the corresponding α-allylated ketones in moderate yield and enantioselectivity.
Nucleophilic phosphanylation of fluoroaromatic compounds with carboxyl, carboxymethyl, and aminomethyl functionalities - An efficient synthetic route to amphiphilic arylphosphanes
Hingst, Martin,Tepper, Michael,Stelzer, Othmar
, p. 73 - 82 (2007/10/03)
Chiral- and multiply-carboxylated phosphanes and phosphanyl derivatives of benzoic and phthalic acids (1-9) are accessible in high yields by nucleophilic phosphanylation of potassium or lithium salts of commercially available fluorobenzoic and 3-fluorophthalic acids with Ph2PH, Ph2PK, PhPLi2, Ph(K)P-(CH2)3-P(K)Ph in superbasic media (DMSO/KOH) or in THF and DME. The hitherto unknown phosphanylphenylacetic acids (10-13) and phosphanylbenzylamines RR′P-C6H4-CH2-NH2 (14-19, R, R′ = H, Me, Ph) with unsubstituted amino groups were also synthesized by this method. The diphenylphosphanyl derivatives 14-16 (R, R′ = Ph) are accessible by an alternative method involving LiAlH4 reduction of the phosphanylbenzonitriles (20-22), which were obtained in high yields by nucleophilic phosphanylation of the corresponding fluoro- or chlorobenzonitriles. The novel bidentate phosphanylbenzonitrile 23 has also been obtained using this synthetic route. All compounds were completely characterized by elemental analysis, NMR spectroscopy, and mass spectrometry.
