Insertion of Isocyanides into the Palladium-Carbon Bond of Cyclopalladated Complexes

Koten, Gerard van; Markies, Bertus A.; Zografidis, Anastassios; Polborn, Kurt; Beck, Wolfgang

doi:10.1515/znb-1994-1107

Cited by 35 publications

(35 citation statements)

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“…It appears that the syn-anti ratio of product is affected by donor atoms present in the pincer arms, which also influence diastereoselectivity. The mechanism for the present catalytic reaction may be at variance with those in which donor atoms in the arms of pincer 94,[154][155][156] are other than Se.…”

Section: Catalytic Aldol Type Of Reactions 94mentioning

confidence: 92%

Organoselenium ligands in catalysis

et al. 2012

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Organoselenium ligands are building blocks of several transition metal complexes which catalyze various organic reactions efficiently in solution. In this review the survey of developments pertaining to the designing of such complexes (along with their Se-ligands), and their uses as catalysts for various organic reactions has been presented with critical analysis of present status of the subject. Undoubtedly a new family of catalysts or their precursors has been generated by organoselenium ligands. The catalytic activity and selectivity of their metal complexes can sometimes be fine-tuned efficiently by changing the ligand's framework. They show good thermal and air-stability. This, coupled with ease in their handling and synthesis, may make them not only attractive but good alternatives to several popular catalysts.

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Section: Catalytic Aldol Type Of Reactions 94mentioning

confidence: 92%

Organoselenium ligands in catalysis

et al. 2012

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“…27 As suggested in the case of compound 5, we cannot rule out for 14a,b an incipient penta-coordination resulting from a weak interaction between the dimethylamino group and Pd, even in solution. This hypothesis is moreover supported by a variable-temperature 31 P{ 1 H} NMR study on 14b. The doublet resonance at d 28.8 for the Pd-bound phosphorus, which is well resolved at ambient temperature, broadens upon progressive cooling and collapses finally at −50 • C to a hump, whereas the resonance of the Fe-bound phosphorus nucleus remains unaffected.…”

Section: Migratory Insertion Reactions Of Organic Isocyanidesmentioning

confidence: 67%

“…From the position of the two doublets at d 60.2 and 28.1 it can be concluded that an increasing high-field shift correlates with an increasing number of inserted isocyanide units within the series 16-18. 38 After addition of a fourth equivalent of o-anisylNC, immediate recording of the IR and 31 The outcome of the insertion reactions appears to depend from the electronic properties of the isocyanide reagent. After addition of two equivalents of the more nucleophilic (and more basic) tert-butyl isocyanide to a solution of [(OC) 3 -Fe{l-Si(OMe) 2 (OMe)}(l-dppm)PdMe], the anticipated bis-(insertion) product was not formed even after 1 h reaction time, but instead the bright yellow complex [(OC) 3 {(MeO) 3 Si}-Fe(l-dppm)Pd{C(=NBu t )Me}(CNBu t )] (21) was isolated in good yield.…”

Section: {C(=n-o-anisyl)c(=n-o-anisyl)me}] (17) and The Tris(insertio...mentioning

confidence: 99%

Insertion reactions of alkynes and organic isocyanides into the palladium–carbon bond of dimetallic Fe–Pd alkoxysilyl complexes

Knorr¹,

Jourdain²,

Braunstein³

et al. 2006

Dalton Trans.

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Insertion of MeO(2)C-C[triple bond]C-CO(2)Me (DMAD) into the Pd-C bond of the heterodimetallic complex [(OC)(3)F[upper bond 1 start]e{mu-Si(OMe)(2)([lower bond 1 start]OMe)}(mu-dppm)P[lower bond 1 end][upper bond 1 end]d(dmba-C)] (2) (dppm = Ph(2)PCH(2)PPh(2), dmba-C = metallated dimethylbenzylamine) and [(OC)(3){(MeO)(3)Si}F[upper bond 1 start]e(mu-dppm)P[upper bond 1 end]d(8-mq-C,N)] (3) (8-mq-C,N = cyclometallated 8-methylquinoline) yielded the sigma-alkenyl complexes [(OC)(3)F[upper bond 1 start]e{mu-Si(OMe)(2)([lower bond 1 start]OMe)}(mu-dppm)P[lower bond 1 end][upper bond 1 end]d{C(CO(2)Me)=C(CO(2)Me)(o-C(6)H(4)CH(2)NMe(2))}] (7) and [(OC)(3)F[upper bond 1 start]e{mu-Si(OMe)(2)([lower bond 1 start]OMe)}(mu-dppm)P[lower bond 1 end][upper bond 1 end]d{C(CO(2)Me)[double bond, length as m-dash]C(CO(2)Me)(CH(2)C(9)H(6)N)}] (8), respectively. The latter afforded the adduct [(OC)(3){(MeO)(3)Si}F[upper bond 1 start]e(mu-dppm)P[upper bond 1 end]d{C(CO(2)Me)=C(CO(2)Me)(CH(2)C(9)H(6)N)}(CNBu(t))] (9) upon reaction with 1 equiv. of Bu(t)NC. The heterodinuclear sigma-butadienyl complexes [(OC)(3)F[upper bond 1 start]e{mu-Si(OMe)(2)([lower bond 1 start]OMe)}(mu-dppm)P[lower bond 1 end][upper bond 1 end]d{C(Ph=C(Ph)C(CO(2)Me)=(CO(2)Me)(o-C(6)H(4)CH(2)NMe(2))}] (11) and [(OC)(3)F[upper bond 1 start]e{mu-Si(OMe)(2)([lower bond 1 start]OMe)}(mu-dppm)P[lower bond 1 end][upper bond 1 end]d{C(Ph)=C(CO(2)Et)C(Ph)=C(CO(2)Et)(CH(2)C(9)H(6)N)}] (13) have been obtained by reaction of the metallate K[Fe{Si(OMe)(3)}(CO)(3)(dppm-P)] (dppm = Ph(2)PCH(2)PPh(2)) with [P[upper bond 1 start]dCl{C(Ph)=C(Ph)C(CO(2)Me)=C(CO(2)Me)(o-C(6)H(4)CH(2)N[upper bond 1 end]Me(2))}] or [P[upper bond 1 start]dCl{C(Ph)=C(CO(2)Et)C(Ph)=(CO(2)Et)}(CH(2)C(9)H(6)N[upper bond 1 end])], respectively. Monoinsertion of various organic isocyanides RNC into the Pd-C bond of 2 and 3 afforded the corresponding heterometallic iminoacyl complexes. In the case of complexes [(OC)(3){(MeO)(3)Si}F[upper bond 1 start]e(mu-dppm)P[upper bond 1 end][upper bond 1 start]d{C=(NR)(CH(2)C(9)H(6)N[upper bond 1 end])}] (15a R = Ph, 15b R = xylyl), a static six-membered C,N chelate is formed at the Pd centre, in contrast to the situation in [(OC)(3)F[upper bond 1 start]e{mu-Si(OMe)(2)([lower bond 1 start]OMe)}(mu-dppm)P[lower bond 1 end][upper bond 1 end]d{C(=NR)(o-C(6)H(4)CH(2)NMe(2))}] (14a R = o-anisyl, 14b R = 2,6-xylyl) where formation of a mu-eta(2)-Si-O bridge is preferred over NMe(2) coordination. The outcome of the reaction of the dimetallic alkyl complex [(OC)(3)F[upper bond 1 start]e{mu-Si(OMe)(2)([lower bond 1 start]OMe)}(mu-dppm)P[lower bond 1 end][upper bond 1 end]dMe] with RNC depends both on the stoichiometry and the electronic donor properties of the isocyanide employed for the migratory insertion process. In the case of o-anisylisocyanide, the iminoacyl complex [(OC)(3)F[upper bond 1 start]e{mu-Si(OMe)(2)([lower bond 1 start]OMe)}(mu-dppm)P[lower bond 1 end][upper bond 1 end]d{C(=N-o-anisyl)Me}] (16) results from the reaction in a 1 : 1 ratio. Addition of three equiv...

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“…Our studies indicate that using electronsupplying substituents, such as sulfur, nitrogen and selenium instead of phosphorus leads to an increase of the amount of the anti product (Table 1). Previous studies indicate that PCP complexes and pincer complexes [50,54] with sulfur or nitrogen atoms in the side arms (such as 1f and 1g) probably react by different mechanisms in aldol reactions. In addition, the difference in the geometric flexibility [55] of complexes 1a-g may also influence the stereochemical outcome of the cyclization reactions.…”

Section: X-ray Structure Of 6amentioning

confidence: 99%

Palladium Pincer Complex‐Catalyzed Condensation of Sulfonimines and Isocyanoacetate to Imidazoline Derivatives. Dependence of the Stereoselectivity on the Ligand Effects

et al. 2007

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Palladium-catalyzed condensation reactions of sulfonimines with isocyanoacetate were performed using various PCP, SCS, SeCSe and NCN pincer complexes as catalysts. The reactions proceeded rapidly (2 h) at room temperature using only 1 mol % pincer complex catalyst without any additives. The electron-deficient and relatively bulky PCP complex provides imidazoline derivatives with a very high syn diastereoselectivity. The applied PCP catalyst proved to be very robust under the applied reaction conditions, as it could be recovered without any decomposition after the completed catalytic process. The stereoselectivity of the condensation reactions is reversed by employing the electron-rich SeCSe type of complexes. Simple palladium salts, such as palladium acetate, PdA C H T U N G T R E N N U N G (OAc) 2 , catalyze the reaction with a poor stereoselectivity. The stereoselectivity of the PCP complex-catalyzed process does not depend significantly on the steric bulk of the sulfonimine component. Mechanistic studies revealed that the PCP complex-catalyzed reaction proceeds via an h 1 -coordinated palladium isocyanoacetate pincer intermediate. This intermediate could also be isolated and its structure was determined by X-ray diffraction. The X-ray structure of this reaction intermediate indicates a surprisingly strong carbon-metal bond between the palladium atom and the coordinated isocyanoacetate molecule. Our mechanistic studies show that the pincer complex catalyst does not undergo redox reactions and, thus it retains a + 2 oxidation state under the catalytic process.

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Insertion of Isocyanides into the Palladium-Carbon Bond of Cyclopalladated Complexes

Cited by 35 publications

References 0 publications

Organoselenium ligands in catalysis

Organoselenium ligands in catalysis

Insertion reactions of alkynes and organic isocyanides into the palladium–carbon bond of dimetallic Fe–Pd alkoxysilyl complexes

Palladium Pincer Complex‐Catalyzed Condensation of Sulfonimines and Isocyanoacetate to Imidazoline Derivatives. Dependence of the Stereoselectivity on the Ligand Effects

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