Air‐Stable, Sterically Hindered Ferrocenyl Dialkylphosphines for Palladium‐Catalyzed C—C, C—N, and C—O Bond‐Forming Cross‐Couplings.

Abstract

which is air-stable even in solution, is shown to be a general ligand for Pd-catalyzed amination, arylation, alkylation and etherification of aryl halides. The first general procedure for reaction of aryl halides with terminal alkylboronic acids without use of toxic or expensive bases is developed based on the utilization of Q-phos. -(KATAOKA, N.; SHELBY, Q.; STAMBULI, J. P.; HARTWIG*, J. F.; J. Org. Chem. 67 (2002) 16, 5553-5566; Dep. Chem., Yale Univ., New Haven, CT 06520, USA; Eng.) -Nuesgen 03-026 2002 Catalysis

Functionalization of N,N-Dialkylferrocenesulfonamides toward Substituted Derivatives

“…Encouraged by these results, we turned our attention to the more challenging amination of 4-chlorobenzonitrile with morpholine. Inspired by Hartwig and co-workers who employed a sterically hindered ferrocenyldialkylphosphine in similar reactions, 41 we treated a mixture of the aryl chloride and amine with Pd(dba)2 as the catalyst source, potassium tert-butoxide as the base in toluene at 100 °C overnight, in the presence of our phosphines 2h, 2i, 18a and 18b. However, none of the four ligands allowed the expected product to be formed satisfactorily, with only traces of the coupled product detected (Scheme 9, bottom).…”

Palladium-Catalyzed Cross-Coupling Reactions: A Powerful Tool for the Synthesis of Agrochemicals

“…A wide range of ligands, bases, and additives can be utilized in cross-couplings. Generally, phosphines (e.g., trialkyl or triaryl phosphines: [P(t-Bu) 3 , PCy 3 , PPh 3 , and di(1adamantyl)-n-butylphosphine]), 27−29 dialkylbiaryl phosphines (e.g., chelating bisphosphine ligands: [BINAP (2,2′-bis-(diphenylphosphino)-1,1′-binaphthyl) 30,31 and dppf (1,1′-bis-(diphenylphosphino)ferrocene)], 32,33 Hartwig's QPhos [pentaphenyl(ditert-butylphosphino)ferrocene], 34,35 Buchwald's XPhos (2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl), 36,37 secondary phosphine oxides, 38 2,2-diphenylvinyl phosphines, 39 etc., are widely used as ligands in cross-coupling reactions. The use of N-heterocyclic carbene (NHC, a cyclic carbene bearing at least one α-amino substituent) variants as alternative ligands in cross-coupling reactions has rapidly been gaining in popularity, widening the substrate scope and resulting in milder reaction conditions.…”

Pd/Gorlos‐Phos‐Catalyzed Chemoselective Amination of Bromophenyl Chlorides with Primary Arylamines

“…[10][11][12][13][14][15][16][17][18] The development of ligands for palladium-catalyzed amination of aryl halides with primary aryl amines has advanced dramatically in recent years, including trialkyl phosphines (P( t Bu) 3 , P(CH 2 t Bu) 3 ), ferrocenyl dialkyl phosphines (CyPF-t BuJosiPhos, DPPF, QPhos, HiersoPhos), dialkyl biaryl phosphines (BrettPhos, RuPhos, t BuBrettPhos), and binaphthyl-derived phosphines (BINAP) (Scheme 1,a). [19][20][21][22][23][24][25][26][27][28][29][30][31][32] In our previous work, we have developed electron-rich and sterically bulky monophosphines LB-Phos, [33][34][35] Zheda-Phos, [36] and Gorlos-Phos [37,38] for the activation of CÀ Cl bonds.…”