Synthesis of an electron-rich KITPHOS monophosphine, preparation of derived metal complexes and applications in catalysis

Abstract

This protocol describes the synthesis of a representative example of the electron-rich biaryl-like KITPHOS class of monophosphine, 11-dicyclohexylphosphino-12-phenyl-9,10-dihydro-9,10-ethenoanthracene (H-KITPHOS). The bicyclic architecture of H-KITPHOS is constructed via [4+2] Diels-Alder cycloaddition between 1-(dicyclohexylphosphinoylethynyl)benzene and anthracene. H-KITPHOS monophosphine is prepared via an operationally straightforward three-step procedure and is isolated in an overall yield of ∼55%. The synthesis of palladium and gold precatalysts of H-KITPHOS are also described; the yields of analytically pure complexes are high (75-85% and 85-90%, respectively). The palladium complex of H-KITPHOS forms a highly active catalyst for C-C and C-N cross-coupling of a range of aryl and heteroaryl chlorides and bromides, and the electrophilic Lewis acid gold complex efficiently catalyzes a host of cycloisomerizations. The total time required for the synthesis of H-KITPHOS is 95 h; the preparation of corresponding palladium and gold precatalysts requires an additional 7-8 h, and, if necessary, crystallizations will require a further 48 h.

Alkyne/Alkene/Allene‐Induced Disproportionation of Cationic Gold(I) Catalyst

“…27 Thus, the decay of active catalyst is expected to be slow. Indeed, low catalyst loadings (0.1 %) have been achieved for this reaction 28. Similarly, the alkyne hydration (Scheme d) reported by Nolan and co‐workers2c and the intramolecular addition of a diol to an alkyne reported by Hashmi and co‐workers2d, 29 have been achieved with very high TONs.…”

“…Indeed, low catalyst loadings (0.1 %) have been achieved for this reaction. [28] Similarly, the alkyne hydration (Scheme 3 d) reported by Nolan and co-workers [2c] and the intramolecular addition of a diol to an alkyne reported by Hashmi and co-workers [2d, 29] have been achieved with very high TONs. In these reactions, the turnoverlimiting determining stage is most likely the protodeauration of [L-Au-S-Nu]-type complex (Scheme 1).…”

Catalytic Oxidative Cyclisation Reactions of 1,6‐Enynes: A Critical Comparison Between Gold and Palladium

“…[1][2][3][4][5][6] Some complexes that are often encountered as catalysts are depicted in Figure 1. Ph 3 PAuCl (1) [7] and IPrAuCl (2) [8] are representatives of the two common types of pre-catalyst that possess phosphine [9] and N-heterocyclic carbene ligands [10] (NHC), respectively. Both types of pre-catalyst show a linear coordination geometry, which is typical of Au(I) complexes.…”

Mechanistic insights and functionalization of alkynes in homogeneous gold catalysis.

“…Indeed, low catalyst loadings (0.1%) have been achieved for this reaction. 109 Similarly, the alkyne hydration (Scheme 8d) reported by Nolan and coworkers, 70 and the intramolecular addition of a diol to an alkyne reported by Hashmi and coworkers 71,110,111 have been achieved with very high turnover numbers. In these reactions, the turnover limit determining stage is most likely the protodeauration of [L-Au-S-Nu] type complex (Scheme 6).…”