Ligand Electronic Effect in Enantioselective Palladium-Catalyzed Copolymerization of Carbon Monoxide and Propene

Gambs, Céline; Chaloupka, Stanislav; Consiglio, Giambattista; Togni, Antonio

doi:10.1002/1521-3773(20000717)39:14<2486::aid-anie2486>3.0.co;2-q

Cited by 62 publications

(32 citation statements)

References 10 publications

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“…[12] Recently it has been reported that electronic effects in palladium catalysts modified with chiral ferrocenyldiphosphanes may increase the differentiation of the two coordinating P atoms and change the catalytic activity in the enantioselective copolymerization of carbon monoxide and propene dramatically. [14] 3009 tion position of the methyl group in the cationic complexes, which are catalyst precursors for the copolymerization of carbon monoxide and 4-tert-butylstyrene (TBS). Interestingly, the use of a precatalyst with a different stereochemistry provides copolymers with a different stereoregularity.…”

Section: Introductionmentioning

confidence: 99%

New Pyridine−Imidazoline Ligands for Palladium-Catalyzed Copolymerization of Carbon Monoxide and Styrene

Bastero

Ruiz

Claver

et al. 2001

Eur. J. Inorg. Chem.

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C1‐symmetrical pyridine−imidazoline ligands have been synthesised and used in the preparation of PdII complexes of general formula [PdMe(NCMe)(N‐N′)][BAr′4] [Ar′ = 3,5‐(CF3)2C6H3]. The introduction of electronically different substituents in the imidazoline moiety determines the coordination position of the methyl group in the cationic complexes, which are catalyst precursors for the copolymerization of carbon monoxide and 4‐tert‐butylstyrene (TBS). Interestingly, the use of a precatalyst with a different stereochemistry provides copolymers with a different stereoregularity.

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Section: Introductionmentioning

confidence: 99%

New Pyridine−Imidazoline Ligands for Palladium-Catalyzed Copolymerization of Carbon Monoxide and Styrene

Bastero

Ruiz

Claver

et al. 2001

Eur. J. Inorg. Chem.

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“…To date, the most active class of ligands is that of C 1 -symmetry ferrocenyldiphosphines 96 (Fig. 10.23 ) [90] . The highest activity was obtained with bulky substituent on the phosphorus bonded to the chiral carbon and withdrawing groups on the aryl ring of the second phosphorus atom.…”

Section: Asymmetric Copolymerization Of Co With Propene and Aliphaticmentioning

confidence: 97%

Asymmetric Carbonylations

Godard

Ruiz

Diéguez

et al. 2010

Catalytic Asymmetric Synthesis

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Transition metal -catalyzed carbonylation is one of the most straightforward tools to obtain fi ne chemicals intermediates from alkenes and other unsaturated products. Together with asymmetric hydrogenation, asymmetric C -C bond formation, and asymmetric allylic substitutions, the asymmetric carbonylations are among the most challenging homogeneous processes. Their potential is still to be made the most of, perhaps because of the complexity of these reactions where aldehydes, esters, or acids can be formed from simple olefi ns and enantiomerically pure products or enantiomeric enrichment of one of the products can be obtained when the transition metal catalyst is modifi ed with a chiral ligand. The most famous asymmetric carbonylation process is the Rh -catalyzed hydroformylation of alkenes, together with the Pd -catalyzed hydroxy -or alkoxycarbonylation of alkenes. There are, however, important differences between these processes, as the rhodium -catalyzed hydroformylation is of greater industrial interest than the palladium carbonylations. From the mechanistic point of view, rhodiumcatalyzed hydroformylation has been much more studied and understood than the palladium -catalyzed carbonylations maybe because of the stability of rhodium species, as well as the applicability of spectroscopic high -pressure (HP) nuclear magnetic resonance (NMR) techniques for the study of the intermediates and the early application of rhodium hydroformylation in industry as " oxo " process. As a result, the last developments in rhodium -catalyzed hydroformylation led to a very good control of the regioselectivity to the desired product as well as the preparation of practically enantiomerically pure aldehydes. Palladium -catalyzed carbonylations, both alkoxycarbonylation and hydroxycarbonylation, have also been widely studied but present more issues to obtain Catalytic Asymmetric Synthesis, Third Edition, Edited by Iwao Ojima

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“…The copolymerization of functionalized terminal alkenes with CO has also been investigated by using [Pd(( S , S ) -27 )(MeCN) 2 ](BF 4 ) 2 as a catalyst [74] . Recently, a modifi ed ( R )( S p ) -JOSIPHOS system ( 29 ) [75,76] was reported to show the highest catalytic activity (1797 g g(Pd) − 1 · h − 1 ) for the copolymerization of propene/CO to give a polymer with complete regioselectivity ( > 99%) and 97.5% of like -diad stereoselectivity. The polymer showed an optical rotation of [ α ] D − 34.6 and circular dichroism of ε = +1.26 in HFIP.…”

Section: Monosubstituted Ethenes and Carbon Monoxidementioning

confidence: 99%