Synthesis of Phosphanylferrocenecarboxamides Bearing Guanidinium Substituents and Their Application in the Palladium‐Catalyzed Cross‐Coupling of Boronic Acids with Acyl Chlorides

Abstract

and 2), respectively. These defined complexes as well as their surrogates generated in situ from the

Synthesis of Hydrophilic Phosphorus Ligands and Their Application in Aqueous‐Phase Metal‐Catalyzed Reactions

“…The catalytic system based on ligand 68 for example exhibited good functional group tolerance giving the desired ketones in moderate to very high yields (Scheme 59). [58] Similar results were obtained using ligands 46 [45] and 22 [34] . In general the best yields were achieved when electron‐rich boronic acids are reacted with electron‐poor benzoyl chlorides.…”

“…Guanidinium Groups . Recently, the guanidine moiety as hydrophilic entity was revisited by the group of Štěpnička for the preparation of phosphinylferrocene ligands [58–60] . Taking advantage of a carboxyl group, which can be transformed into its acylbenzotriazole derivative, an acylguanidinium moiety could be efficiently installed (Scheme 23).…”

“…Taking advantage of a carboxyl group, which can be transformed into its acylbenzotriazole derivative, an acylguanidinium moiety could be efficiently installed (Scheme 23). [58] …”

“…The corresponding alkylguanidinium ligand 68 incorporating an aliphatic spacer was synthesized by a standard amide coupling reaction (Scheme 24). [58] Both ligands ( 67 and 68 ) were air stable and although not particularly water‐soluble they could be used for Pd‐catalyzed cross‐couplings in biphasic reaction media.…”

Synthesis and Catalytic Evaluation of Phosphanylferrocene Ligands with Cationic Guanidinium Pendants and Varied Phosphane Substituents

“…The highly polar and positively charged guanidinium moiety has been used to modify inherently hydrophobic phosphane molecules, in particular, to increase their affinity towards polar solvents and water, In catalysis, the guanidinium unit can further act as a structure‐controlling moiety, which exploits its hydrogen‐bonding ability to stabilize a specific structure (e.g., the structure of a reaction intermediate) and to direct molecular parts or reaction partners to specific positions . In the chemistry of ferrocene phosphanes, however, the guanidine modifying group has been utilized only scarcely (see compounds A and B in Scheme ) …”