Homo- and Heteroannularly Bridged Ferrocenyl Diphosphines in Asymmetric Hydrogenations

Sturm, Thomas; Weissensteiner, Walter; Spindler, Felix; Mereiter, Kurt; López-Agenjo, Ana; Manzano, Blanca R.; Jalón, Félix A.

doi:10.1021/om0107439

Cited by 62 publications

(24 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During hydrogenation of 10a a characteristic pale yellow solution, which indicates formation of the Ir À H catalyst, was not observed. [15] Thus leading us to attribute the absence of any activity with imine 10a to the formation of a stable Ir-imine complex.…”

Section: Solvent/catalyst Precursor Effectsmentioning

confidence: 99%

Chiral Diphosphine ddppm‐Iridium Complexes: Effective Asymmetric Imine Hydrogenations at Ambient Pressures

2006

View full text Add to dashboard Cite

Complexes of the type [Ir(ddppm)(COD)]X were prepared and tested in the asymmetric hydrogenation of a range of imine substrates. Contrary to known iridium catalysts, the ddppm complexes formed efficient catalysts under an atmospheric hydrogen pressure, whereas at higher pressures the catalytic activity of the system was drastically reduced. Depending upon the reaction conditions, N-arylimines, Ar'N ¼ CMeAr, were hydrogenated to the corresponding secondary amines in high yields and enantioselectivities (80 -94% ee with molecular hydrogen at atmospheric pressure and were found to inhibit catalytic activity.

show abstract

Section: Solvent/catalyst Precursor Effectsmentioning

confidence: 99%

Chiral Diphosphine ddppm‐Iridium Complexes: Effective Asymmetric Imine Hydrogenations at Ambient Pressures

2006

View full text Add to dashboard Cite

show abstract

“…As far as we know, only chiral ferrocenophanes bearing carbon tethers between the Cp rings and attached R 2 P functions, have been used so far in asymmetric catalysis. [14] We started our study by considering the use as catalysts of 2-phospha [3]ferrocenophanes with stereogenic carbon atoms in the tethering chain (I). [12] Their preliminary evaluations in a model organocatalytic reaction (Scheme 1) have highlighted, however, a major drawback of the targeted structures.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Chiral 2‐Phospha[3]ferrocenophanes and their Behaviour as Organocatalysts in [3+2] Cyclization Reactions

et al. 2009

View full text Add to dashboard Cite

Planar chiral 2-phospha[3]ferrocenophanes have been prepared via a stereoselective three-step synthesis. The key step is the lithiation of the 1,1'-di-A C H T U N G T R E N N U N G substituted ferrocene 11 bearing (S)-2-(methoxymethyl)pyrrolidines as the chiral ortho-directing groups. The diastereoselectivity of these reactions has been mastered by an appropriate choice of the metallating agent, so as to afford a suitable access to C 2 -symmetrical, tetrasubstituted ferrocenes. These compounds have been converted into the enantiomerically pure 2-phospha[3]-ferrocenophanes 16, via the corresponding acetates and their reactions with primary phosphines. Phosphines 16 have been used as nucleophilic catalysts in model cyclization reactions. Unlike 2-phospha[3]-ferrocenophanes with stereogenic acarbons, the planar chiral derivatives 16 proved to be suitable catalysts for these processes. Thus, for instance, phosphine 16c successfully promotes the enantioselective [3 + 2] annulations of allenes and enones into functionalized cyclopentenes (ees up to 96%). Among others, spirocyclic derivatives have been obtained in good yields and ees in the range 77-85%. The robustness of this catalyst has been demonstrated by recycling experiments.

show abstract

“…[1,2] Weissensteiner et al have developed a variety of such ligands derived from the [3]ferrocenophane framework, [3] among them enantiomerically pure examples. [4,5] They had further shown that the chiral bis(phosphanyl) [3]ferrocenophane ligands appeared to be inferior with regard to asymmetric induction, e.g. in some hydrogenation reactions as compared e.g.…”

Section: Introductionmentioning

confidence: 99%

“…to the JOSIPHOS system and related less rigid ligands. [4] Recently we have found that bis(phosphanyl) [3]ferrocenophane ligands may be of some use in alternating CO/olefin copolymerization. [6] We had developed a very simple way to synthesize such systems starting from 1,1Ј-diacetylferrocene (1) by a reaction sequence that was initiated by an intramolecular Mannich-type coupling omers, respectively.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Enantiomerically Pure [3]Ferrocenophane‐Based Chelate Bis‐Phosphane Ligands and Their Use in Asymmetric Alternating Carbon Monoxide/Propene Copolymerization

et al. 2005

View full text Add to dashboard Cite

An intramolecular Mannich reaction (HNMe2, TiCl4) was used to convert 1,1'‐diacetylferrocene to the unsaturated amino[3]ferrocenophane 2. Subsequent hydrogenation gave 3. To obtain enantiomerically pure chelate P,P‐[3]ferrocenophane ligands the readily available pure dimethylamino[3]ferrocenophane enantiomers (R,R)‐3 and (S,S)‐3 each were treated with butyllithium followed by chlorodiphenylphosphane to yield the chelate P,N‐[3]ferrocenophanes (R,R,Rpl)‐10 and (S,S,Spl)‐10, respectively. Their treatment with HPPh2 in glacial acetic acid resulted in substitution of the –NMe2 group by –PPh2 with overall retention of configuration to yield (R,R,Rpl)‐11 and (S,S,Spl)‐11, respectively (both characterized by X‐ray diffraction). Similarly, the reaction of (R,R,Rpl)‐10 or (S,S,Spl)‐10 with dicyclohexylphosphane/HOAc yielded the pure (R,R,Rpl)‐12 and (S,S,Spl)‐12 enantiomers, respectively. Both these compounds were also characterized by X‐ray crystal structure analyses. (R,R,Rpl)‐12 was employed in catalytic asymmetric hydrogenation and also in asymmetric alternating carbon monoxide/propene copolymerization. A catalyst that was generated in situ from the chelate P,P‐[3]ferrocenophane ligand and palladium acetate gave the CO/propene alternating copolymer with a good activity and high asymmetric induction. The catalyst derived from the reaction of (R,R,Rpl)‐11 with [Rh(cod)2]BF4 was employed in the enantioselective hydrogenation of dimethyl itaconate (DMI) (13, ca. 95 % ee, R‐configured product) and methyl α‐acetamidocinnamate (MAC) 14 (ca. 24 % ee, R‐configured product). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

show abstract

Homo- and Heteroannularly Bridged Ferrocenyl Diphosphines in Asymmetric Hydrogenations

Cited by 62 publications

References 14 publications

Chiral Diphosphine ddppm‐Iridium Complexes: Effective Asymmetric Imine Hydrogenations at Ambient Pressures

Chiral Diphosphine ddppm‐Iridium Complexes: Effective Asymmetric Imine Hydrogenations at Ambient Pressures

Synthesis of Chiral 2‐Phospha[3]ferrocenophanes and their Behaviour as Organocatalysts in [3+2] Cyclization Reactions

Preparation of Enantiomerically Pure [3]Ferrocenophane‐Based Chelate Bis‐Phosphane Ligands and Their Use in Asymmetric Alternating Carbon Monoxide/Propene Copolymerization

Contact Info

Product

Resources

About