Manganese catalyzed α-methylation of ketones with methanol as a C1 source

Abstract

The direct α-methylation of ketones with methanol under hydrogen borrowing conditions using a well-defined manganese PN3P pre-catalyst was, for the first time, achieved.

α‐Methylation of Ketones with Methanol Catalyzed by Ni/SiO2‐Al2O3

“…This undesired product is probably formed by the Michael addition of 1a on the product of aldol‐condensation between formaldehyde and propiophenone. This kind of product has been previously observed by other groups , . Although a high conversion was obtained with K 2 CO 3 , the yield was still moderate (45 % GC ratio, Table , entry 4).…”

“…This reaction has been mainly reported with homogeneous Ir, Ru and Rh complexes (Scheme a). More recently, it has been shown that non‐noble metal complexes of Co, Mn, Ni and Fe could efficiently catalyze this reaction (Scheme b). Pd supported on polymers and Pt/C are the only examples of heterogeneous catalysts for the α‐methylation of ketones with methanol (Scheme c).…”

Manganese‐Catalyzed One‐Pot Conversion of Nitroarenes into N‐Methylarylamines Using Methanol

“…To commence our studies, the one‐pot conversion of nitrobenzene 1 to N ‐methylaniline 2 was selected as the model system (Table ). After extensive optimization, it was found that a catalytic system composed of the well‐defined bench stable Mn PN 3 P pincer precatalyst 3 (5 mol‐%) introduced by Sortais and co‐workers, and KOH (2 equiv.) as base in MeOH ([ 1 ] = 0.5 m ) with 4 Å molecular sieves at 110 °C for 16 h gave 2 in 94 % NMR yield and 90 % isolated yield (entry 1).…”

Transition Metal-Catalyzed α-Position Carbon–Carbon Bond Formations of Carbonyl Derivatives

“…Stable manganese-PNP (Scheme 21b) [36] and cobalt-PNP complexes (Scheme 21c) [37] provide α-alkylated ketones with the use of benzylic alcohol derivatives. Recently, Sortais and coworkers demonstrated the metal-catalyzed hydrogen-borrowing α-alkylation of ketones with methanol in the presence of their manganese-PN 3 P complex (Scheme 21d) [38].…”

“…Pd catalyst and monodentate phosphine ligand Aldehydes Allylation [14] Arylation [15][16][17] Imines Allylation [41][42][43] Pd catalyst and DPPF ligand Ketones Allylation [33,34] Pd catalyst and diphenylbisphosphine ligand Ketones Allylation [31] Amides Allylation [46,47] Pd catalyst and dialkylbisphosphine ligand Amides Arylation [48] Pd catalyst and pyrrolidine organocatalyst Aldehydes Allylation [18,19] Pd catalyst and phosphoric acid Aldehydes Allylation [20][21][22][23] Pd catalyst and DIAPHOX ligand Ketones Allylation [32] Ru catalyst and PNN ligand Amides Alkylation [49] Rh catalyst and BINAP ligand Aldehyde Allylation [25] Ir catalyst and P-olefin & amine Aldehydes Allylation [24] Ir catalyst and monodentate phosphine ligand Esters Alkylation [50] Ni catalyst and Mandyphos ligand Amides Acylation [51] Co catalyst and PNP ligand Ketones Alkylation [37] Co catalyst and PN 5 P ligand Amides Esters Alkylation [52] Mn catalyst and PN n P ligand Ketones Alkylation [36,38] Ni catalyst and NNN ligand Amides Esters Alkylation [53] Rh catalyst and NHC ligand Ketones Alkylation [39] Ru(bpy) 3 photocatalyst Aldehydes Alkylation [26,27,30] Ketones Alkylation [40] Imines Alkylation [45] Ir photocatalyst Aldehydes Alkylation [28,29] Catalysts Allylic alkylation and ...…”