Non‐Pincer‐Type Manganese Complexes as Efficient Catalysts for the Hydrogenation of Esters

Abstract

Catalytic hydrogenation of carboxylic acid esters is essential for the green production of pharmaceuticals, fragrances, and fine chemicals. Herein, we report the efficient hydrogenation of esters with manganese catalysts based on simple bidentate aminophosphine ligands. Monoligated Mn PN complexes are particularly active for the conversion of esters into the corresponding alcohols at Mn concentrations as low as 0.2 mol % in the presence of sub‐stoichiometric amounts of KOtBu base.

Retracted: The Manganese(I)‐Catalyzed Asymmetric Transfer Hydrogenation of Ketones: Disclosing the Macrocylic Privilege

“…Driven by the importance of enantiopure alcohols, [2] iron catalysts have been developed for the asymmetric hydrogenation of polar double bonds. [3][4][5][6][7] In contrast, manganese remained unexplored until 2016, when it was applied in the non-enantioselective hydrogenation of polar multiple bonds with H 2 [8][9][10][11][12][13][14][15] and, more rarely,u nder hydrogen-transfer conditions. [16][17][18] Similarly,e nantioselective Mn I catalysts for ketone hydrogenation with H 2 (Clarke: A, [19] Beller: B, [20] Han and Ding: C, [21] and ours: D [22] )a re more numerous than those for asymmetric transfer hydrogenation (E [23] and F [24] ; Figure 1).…”

Manganese‐Catalyzed Direct Olefination of Methyl‐Substituted Heteroarenes with Primary Alcohols

“…Table features key results of the optimization of the manganese‐catalyzed direct dehydrogenative olefination reaction of 2‐methylpyrazine ( 1 a ) with benzyl alcohol ( 2 a ; see the Supporting Information for details). Inspired by recent studies, we realized that in situ catalyst formation with inexpensive, readily available, and bench‐stable nitrogen donor ligands would enable more rapid optimization ,,. The hydrazone‐based pincer ligand L6 was found to be ideal, delivering the product ( E )‐2‐styrylpyrazine ( 3 aa ) in 96 % yield (Table , entry 6).…”

Biomimetic Hydrogenation Catalyzed by a Manganese Model of [Fe]‐Hydrogenase

“…For comparison, the previous model 4 afforded only a yield of 43 % under the same conditions. We also tested complexes 11 [11] and 12, [12] which were highly active in the hydrogenation of common organic substrates. However, no hydrogenation of 9 a was observed.…”