02052nas a2200277   4500008004100000022001400041245011600055210006900171260000800240300001500248490000900263520112800272653002901400653001401429653001901443653002201462653003101484100001701515700001701532700002201549700001501571700001701586700001701603700002401620856013001644       2022                        eng d  a1434-193X00aMechanistically guided one pot synthesis of phosphine-phosphite and its implication in asymmetric hydrogenation0 aMechanistically guided one pot synthesis of phosphinephosphite a  cJAN  ae2021014470 v20223 a<p>
	Although hybrid bidentate ligands are known to yield highly enantioselective products in asymmetric hydrogenation (AH), synthesis of these ligands is an arduous process. Herein, a one pot, atom-economic synthesis of a hybrid phosphine-phosphite (L1) is reported. After understanding the reactivity difference between an 0-nucleophile versus C-nucleophile, one pot synthesis of Senphos (L1) was achieved (72%). When L1 was treated with [Rh], P-31 NMR revealed bidentate coordination to Rh. Senphos, in the presence of rhodium, catalyzes the AH of Methyl-2-acetamido-3-phenylacrylate and discloses an unprecedented turn over frequency of 2289, along with excellent enantio-selectivity (92%). The generality is demonstrated by hydrogenating an array of alkenes. The AH operates under mild conditions of 1-2 bar H-2 pressure, at room temperature. The practical relevance of Ll is demonstrated by scaling-up the reaction to 1 g and by synthesizing DOPA, a drug widely employed for the treatment of Parkinson's disease. Computational insights indicate that the R isomer is preferred by 3.8 kcal/mol over the S isomer.</p>
10aasymmetric hydrogenation10acatalysis10aDOPA synthesis10aOne pot synthesis10aPhosphine-phosphite ligand1 aSen, Anirban1 aKumar, Rohit1 aPandey, Swechchha1 aRaj, Vipin1 aKumar, Pawan1 aVanka, Kumar1 aChikkali, Samir, H.  uhttp://library.ncl.res.in/content/mechanistically-guided-one-pot-synthesis-phosphine-phosphite-and-its-implication-asymmetric01983nas a2200229   4500008004100000022001400041245008100055210006900136260000900205300000800214490000800222520124900230653001401479653001701493653002101510653003101531653002101562100001701583700001701600700002401617856011201641       2023                        eng d  a0974-362600aRh-catalyzed asymmetric hydroformylation of olefins using phosphorus ligands0 aRhcatalyzed asymmetric hydroformylation of olefins using phospho  cNOV   a1080 v1353 a<p>Easily accessible BINOL-based monodentate phosphite ligand L1 and hybrid ligand L2 have been synthesized in good yield by following a one-pot, two-step protocol. A single 31P resonance at 146.6 ppm confirmed the formation of L1. Subsequent 1-2D NMR and mass spectrometric analysis authenticated the existence of L1. These ligands afforded excellent activity and regio-selectivity in the Rh-catalyzed AHF of styrenic substrates. L1 showed excellent regioselectivity but did not discriminate between the two enantiomers, while L2 displayed an enantiomeric excess (ee) of up to 20%. In our attempts to understand the reasons for low ee, the coordination behavior of L2 was investigated. The coordination study revealed that L2 coordinates with the Rh as a monodentate ligand, although there are two P-sites. It was found that only the phosphine arm was coordinated to the Rh and the phosphite arm stayed away from the Rh core at the ambient temperature, leading to moderate ee.Graphical abstractOne-step synthesis of a phosphite (L1) and a phosphine-phosphite (L2) ligand and their implication in the asymmetric hydroformylation of olefins with excellent regioselectivity (&gt;95%) and moderate enantioselectivity (up to 20%) is reported.</p>
10acatalysis10acoordination10aHydroformylation10aPhosphine-phosphite ligand10aPhosphite ligand1 aKumar, Rohit1 aSen, Anirban1 aChikkali, Samir, H.  uhttp://library.ncl.res.in/content/rh-catalyzed-asymmetric-hydroformylation-olefins-using-phosphorus-ligands