We provide a new transfer hydrogenation of structurally diverse aldehydes and ketones in water using formic acid as hydride donor. The iridium complex of 4,4′,5,5′-tetrahydro-1H,1′H-2,2′-biimidazole, is used as the efficient catalyst. The S/C ratios in aldehyde and ketone reductions are as low as 20,000 and 10,000, respectively. The TOF value in aldehyde reduction is as high as 60,000 h⁻¹. A number of functional groups such as (hetero)aryl, alkenyl, halogen, phenolic and alcoholic hydroxyls, trifluromethyl, cyano, nitro, ester, carboxylic acid, and acidic methylenes are well tolerated.

中文翻译：

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铱催化高效转移加氢还原水中的醛和酮

我们使用甲酸作为氢化物供体，提供了水中结构多样的醛和酮的新型转移加氢反应。复杂的4,4铱'，5,5'-四氢ħ，1' ħ -2,2'-联咪唑，被用作有效的催化剂。醛和酮还原的S / C比分别低至20,000和10,000。醛还原中的TOF值高达60,000 h ^-1。很好地耐受许多官能团，例如（杂）芳基，烯基，卤素，酚和醇羟基，三氟甲基，氰基，硝基，酯，羧酸和酸性亚甲基。