01240nas a2200289 4500008004100000022001400041245005300055210005300108260000800161300001200169490000600181520040000187653002900587653001400616653002200630653001200652653001600664100002000680700001700700700002700717700002400744700002500768700002500793700002400818700002400842856008400866 2020 eng d a2193-580700aHighly enantioselective synthesis of sitagliptin0 aHighly enantioselective synthesis of sitagliptin cFEB a189-1910 v93 a

A highly enantioselective synthesis of sitagliptin, a potent DPP-4 inhibitor, is reported. Explicitly identified chiral FerroLANE ligands in the presence of rhodium catalyze the asymmetric hydrogenation of an enamine to yield sitagliptin with excellent enantioselectivity (98% ee). The process was scaled up to 5 g and the final product was isolated as a phosphate salt with >99% ee.

10aasymmetric hydrogenation10acatalysis10aFerroLANE ligands10aRhodium10asitagliptin1 aKhopade, Kishor1 aSen, Anirban1 aBirajdar, Rajkumar, S.1 aPaulbudhe, Uday, P.1 aKavale, Dattatry, S.1 aShinde, Prashant, S.1 aMhaske, Santosh, B.1 aChikkali, Samir, H. uhttp://library.ncl.res.in/content/highly-enantioselective-synthesis-sitagliptin02036nas a2200289 4500008004100000022001400041245013000055210006900185260000800254300001400262490000700276520106100283653002601344653003101370653001201401653001401413653001701427100002501444700001701469700002401486700002101510700002701531700002401558700002101582700002401603856011901627 2020 eng d a2192-650600aPalladium-catalyzed insertion of ethylene and 1,1-disubstituted difunctional olefins: an experimental and computational study0 aPalladiumcatalyzed insertion of ethylene and 11disubstituted dif cJUN a1200-12090 v853 a

Insertion or coordination copolymerization of ethylene with di-substituted olefins is challenging and the choice of di-substituted mono-functional olefin versus di-substituted di-functional olefin (DDO) appears to be decisive. Here we show that DDO-inserted species are amenable to ethylene insertion and polymerization. DDOs such as 2-acetamidoacrylic acid (AAA), methyl 2-acetamidoacrylate (MAAA), and ethyl 2-cyanoacrylate (ECA) were treated with palladium complex [{P perpendicular to O}PdMe(L)] (P perpendicular to O=kappa(2)-P,O-Ar2PC6H4SO2O with Ar=2-MeOC6H4; L=C2H6OS) and the existence of respective insertion intermediates in moderate yield (up to 37 %) was established. These intermediates were exposed to ethylene and corresponding ethylene-inserted products were isolated and characterized. A careful comparison with three model compounds confirmed ethylene insertion and polymerization. Thus, the combined experimental and computational investigations show that DDO-inserted species can undergo ethylene insertion and polymerization.

10aHomogeneous catalysis10ainsertion copolymerization10aOlefins10aPalladium10aPolyethylene1 aGaikwad, Shahaji, R.1 aPatel, Ketan1 aDeshmukh, Satej, S.1 aMote, Nilesh, R.1 aBirajdar, Rajkumar, S.1 aPandole, Satish, P.1 aChugh, Jeetender1 aChikkali, Samir, H. uhttp://library.ncl.res.in/content/palladium-catalyzed-insertion-ethylene-and-11-disubstituted-difunctional-olefins03063nas a2200229 4500008004100000022001400041245006500055210006300120260000900183300001100192490000800203520233200211653001302543653002802556653002702584653002902611653003102640653001702671100002702688700002402715856009402739 2021 eng d a0014-305700aInsertion copolymerization of functional olefins: Quo Vadis?0 aInsertion copolymerization of functional olefins Quo Vadis cJAN  a1101830 v1433 a

Functional polyethylene is a specialty polymer with unique set of properties and caters to a niche market. Currently, it is manufactured using high-pressure, high-temperature radical polymerization, or post-reactor (indirect) modification methods. Insertion copolymerization of functional olefins with ethylene provides a low pressure, direct route to prepare functional polyethylenes. However, insertion copolymerization of functional olefins with ethylene poses several impediments and requires special considerations. This review presents the current strategies, examines the progress, and attempts to gauge the commercial potential of direct synthesis of functional polyethylene. The performance of late transition metal catalysts derived from a-diimine, imine-phenolate, phosphine-sulfonate, bis-phosphine-mono-oxide, carbene-phenolate, phosphine-phenolate and their derivatives in the insertion copolymerization of functional olefins with ethylene is evaluated. While catalyst designing is crucial, incorporation of polar olefins that can serve an additional purpose is equally important. Therefore, we have organized the review in the following sections, polar alkenes with- acrylates, acrylic acids, acetates, nitriles, ethers, halides, two functional groups, cross-linking groups, dynamic interactions/self-healing properties, additional function/purpose, renewable functional olefins, and examine the progress. Among these, acrylates have been most intensively investigated and have been successfully incorporated in the polyethylene main-chain. Ethylene, methyl acrylate copolymers prepared by direct copolymerization reveal comparable melting temperature to that of LLDPE (at similar co-monomer content) and unfold the commercial potential of these materials. Recent developments on the insertion copolymerization of renewable functional olefins and di-functional olefins have elicited significant interest. This strategy is being viewed as a means of reducing environmental impact and enabling high functional group density at the same extent of incorporation. The overview thus offers a succinct account of insertion copolymerization of functional olefins, sheds light on the copolymer microstructure/material properties, and initiates a discussion on the commercial potential of functional polyethylene.

10aCatalyst10aFunctional polyethylene10afunctional polyolefins10aHydrophilic polyethylene10ainsertion copolymerization10aPolyethylene1 aBirajdar, Rajkumar, S.1 aChikkali, Samir, H. uhttp://library.ncl.res.in/content/insertion-copolymerization-functional-olefins-quo-vadis02262nas a2200217 4500008004100000022001400041245011800055210006900173260000800242300001400250490000700264520147700271100002701748700002401775700002701799700001901826700002201845700002301867700002401890856013001914 2023 eng d a1759-995400aPalladium-catalyzed polar solvent empowered synthesis of hyper-branched ethylene oligomers and their applications0 aPalladiumcatalyzed polar solvent empowered synthesis of hyperbra cJUL a3239-32510 v143 a

In this contribution, we report the synthesis of two naphthoxy imine ligands, 2-(((2,6-dibenzhydryl-4-methoxyphenyl)imino)methyl)naphthalen-1-ol (L1) and 2-(((2,6-diisopropylphenyl)imino)methyl)naphthalen-1-ol (L2), with different steric and electronic features. L1 and L2 were treated with [(TMEDA)PdMe2] to obtain the corresponding neutral palladium(ii) complexes Cat.1 and Cat.2 in excellent yields. The identity of Cat.1 and Cat.2 was unambiguously ascertained using a combination of spectroscopic and analytical methods, including single-crystal X-ray diffraction. When exposed to 5 bar ethylene pressure, Cat.1 produced hyperbranched ethylene oligomers. The microstructure analysis of ethylene oligomers confirmed the existence of methyl, ethyl, propyl, and sec-butyl branches, with a molecular weight (M-n) of 500-1400 g mol(-1), a PDI of 1.46-2.10, and 67-106 branches per 1000 carbon atoms. The use of a polar solvent, tetrahydrofuran, led to a remarkable 3-fold increase in oligomerization activity without compromising the branching and molecular weight. The resultant hyperbranched ethylene oligomers were selectively monofunctionalized using industrially practiced hydroformylation, ozonolysis, and epoxidation, almost quantitatively. The hydroxy functionalized ethylene oligomer (F4) (5 wt%) was melt-compounded with LLDPE and Nylon-6 to produce a tough yet flexible blend with a higher strain-to-failure as compared to an uncompatibilized blend.

1 aBirajdar, Rajkumar, S.1 aGonnade, Rajesh, G.1 aPol, Harshawardhan, V.1 aPrabhu, Basava1 aRokade, Dhammaraj1 aNandimath, Sheetal1 aChikkali, Samir, H. uhttp://library.ncl.res.in/content/palladium-catalyzed-polar-solvent-empowered-synthesis-hyper-branched-ethylene-oligomers-and