Palladium‐Catalyzed Allylation of Pronucleophiles with Alkynes at 50 °C – Remarkable Effect of 2‐(Dicyclohexylphosphanyl)‐2′‐(dimethylamino)biphenyl as Ligand

Abstract

The allylation of various pronucleophiles 1a–i with 1‐phenylprop‐1‐yne (2) proceeded very smoothly at 50 °C in the presence of catalytic amounts of Pd2(dba)3·CHCl3 (5 mol‐%) and 2‐(dicyclohexylphosphanyl)‐2′‐(dimethylamino)biphenyl (I; 20 mol‐%) in toluene, whilst when Pd(PPh3)4 or Pd2(dba)3·CHCl3/PPh3 were used, the reaction needed 100 °C for completion.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Alkynes as Electrophilic or Nucleophilic Allylmetal Precursors in Transition‐Metal Catalysis

“…The use of α‐branched or cyclic β‐dicarbonyl pronucleophiles led to racemic all‐carbon quaternary stereocenters being formed in an efficient manner (Scheme ) . Improvements to these conditions were subsequently disclosed: these transformations could be conducted at significantly lower temperatures (50 °C) by using DavePhos as a ligand . A solvent‐free, microwave‐assisted version decreased the reaction time to only a few minutes .…”

Biarylphosphanliganden in der palladiumkatalysierten Aminierung

“…[2] Als Liganden für Gold, [3][4][5][6][7][8][9][10][11] Silber, [12] Rhodium, [13,14] Ruthenium [15][16][17] und Kupfer [18] verbesserten diese Phosphane die Reaktivität und Katalysatorstabilität. Die weitaus größte Bedeutung hatten sie aber für palladiumkatalysierte Reaktionen wie die Sonogashira-, [19] Negishi-, [20] Hiyama-, [21][22][23] Kumada- [24] und Suzuki-Kreuzkupplung [25][26][27][28][29][30] , die Heck-Reaktion, [31][32][33] die Enolatarylierung [34][35][36][37] und -allylierung, [38] die reduktive Cyclisierung [39] und Veretherung, [40][41][42][43] die Silylierung, [44] Borylierung, [45][46][47] Cyanierung, [48,49] Methylierung,…”

Biaryl Phosphane Ligands in Palladium‐Catalyzed Amination

“…[2] These phosphines have been used as ligands for gold, [3][4][5][6][7][8][9][10][11] silver, [12] rhodium, [13,14] ruthenium [15][16][17] and copper [18] where they have been shown to impart improvements in reactivity and catalyst stability. It is in reactions catalyzed by palladium, however, that they have had by far the greatest impact including the Sonogashira, [19] Negishi, [20] Hiyama, [21][22][23] Kumada [24] and Suzuki [25][26][27][28][29][30] cross-coupling reactions, Heck reaction, [31][32][33] enolate arylation [34][35][36][37] and allylation, [38] reductive cyclization [39] and etherification, [40][41][42][43] silylation, [44] borylation, [45][46][47] cyanation, [48,…”