ChemInform Abstract: Gold(I) Complexes of KITPHOS Monophosphines: Efficient Cycloisomerization Catalysts

Hashmi, A. Stephen K.; Loos, Annette; Littmann, Anna; Braun, Ingo; Knight, Julian G.; Doherty, Simon; Röminger, Frank

doi:10.1002/chin.200929034

Cited by 2 publications

(1 citation statement)

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“…In this regard, we have recently extended this cycloaddition methodology to the Diels-Alder reaction between 1-alkynylphosphine oxides and anthracene to afford the electron-rich biaryl-like KITPHOS class of monophosphines 50-52 -architectural analogs of Buchwald's biaryl-like monophosphines [53][54][55][56] . Preliminary studies have shown that these monophosphines are highly efficient ligands that either rival or outperform their biaryl-based counterparts in palladium-catalyzed Suzuki-Miyaura and Buchwald-Hartwig cross-couplings 50,51 , a host of gold(I)-catalyzed intramolecular cycloisomerizations [57][58][59] , as well as in the ruthenium-catalyzed direct ortho arylation of 2-phenylpyridine and N-phenylpyrazole with aryl chlorides 60 . In addition, biaryl monophosphines have also been prepared by rhodium-catalyzed [2 + 2 + 2] cycloaddition [61][62][63] and Diels-Alder cycloaddition extrusion 64 .…”

Section: Simon Doherty and Catherine H Smythmentioning

confidence: 99%

Synthesis and resolution of the biaryl-like diphosphine (S)-Me2-CATPHOS, preparation of a derived rhodium precatalyst and applications in asymmetric hydrogenation

Doherty

Smyth

2012

Nat Protoc

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This protocol describes the synthesis of a representative example of the enantiopure biaryl-like CATPHOS class of diphosphines, (S)-9,9'-dimethyl-9,9',10,10'-tetrahydro-9,10,9',10'-biethenobianthracene-11,11'-bis(diphenylphosphino)-12,12'-diyl ((S)-Me(2)-CATPHOS), and its derived cationic rhodium-based hydrogenation precatalyst. The C(2)-symmetric framework of Me(2)-CATPHOS is the result of a regioselective Diels-Alder cycloaddition between 1,4-bis(diphenylphosphinoyl)buta-1,3-diyne and 9-methylanthracene, such that the bulky methyl-substituted bridgehead carbon atoms are attached to C2 and C3 of the 1,3-butadiene tether. Enantiopure Me(2)-CATPHOS is obtained in an operationally straightforward three-step procedure and isolated in ∼50-60% overall yield and <99% enantiopurity, after diastereoselective resolution with (2R,3R)-(-)-2,3-O-dibenzoyltartaric acid. The derived rhodium complex forms a highly effective catalyst for the asymmetric hydrogenation of a range of dehydroamino acid derivatives, as well as (E)-β-aryl-(enamido)phosphonates, giving ee values in excess of 99%, the highest to be reported for the latter class of substrate. The total time required for the synthesis of (S)-Me(2)-CATPHOS, including resolution, reduction and crystallizations, is 130 h and preparation of the corresponding rhodium precatalyst requires an additional 24-26 h.

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Section: Simon Doherty and Catherine H Smythmentioning

confidence: 99%

Synthesis and resolution of the biaryl-like diphosphine (S)-Me2-CATPHOS, preparation of a derived rhodium precatalyst and applications in asymmetric hydrogenation

Doherty

Smyth

2012

Nat Protoc

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Gold coordination during homogeneous alkyne and allene cyclisation catalysis: Coordination to substrates, to ancillary ligands and in intermediates

Raubenheimer¹,

Schmidbaur²

2011

S Afr J Sci

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The ever-increasing role of homogeneous gold catalysis in organic synthesis and the consequent need to be able to rationally control the rate and outcome of such reactions has emphasised the importance of each successive metal-carbon coordination step. Concentrating on alkyne and allene cyclisation and upon reaction mechanisms postulated on the basis of empirical and theoretical results, we have examined the coordination of gold fragments to triple bonds, the modification of gold(I) precatalysts to effect specific reaction pathways or enantioselectivity and the isolation of coordinated intermediates or model compounds thereof. Some of the recent advances that have been made in various laboratories are described in this compact review.

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ChemInform Abstract: Gold(I) Complexes of KITPHOS Monophosphines: Efficient Cycloisomerization Catalysts

Abstract: Ring closure reactions O 0130Gold (I) Complexes of KITPHOS Monophosphines: Efficient Cycloisomerization Catalysts -[all yields determined by NMR]. -(HASHMI*, A. S. K.; LOOS, A.; LITTMANN, A.; BRAUN, I.; KNIGHT, J.; DOHERTY, S.; ROMINGER, F.; Adv.

Cited by 2 publications

References 1 publication

Synthesis and resolution of the biaryl-like diphosphine (S)-Me2-CATPHOS, preparation of a derived rhodium precatalyst and applications in asymmetric hydrogenation

Synthesis and resolution of the biaryl-like diphosphine (S)-Me2-CATPHOS, preparation of a derived rhodium precatalyst and applications in asymmetric hydrogenation

Gold coordination during homogeneous alkyne and allene cyclisation catalysis: Coordination to substrates, to ancillary ligands and in intermediates

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