Recent advances of Cp*Ir complexes for transfer hydrogenation: focus on formic acid/formate as hydrogen donors

Abstract

This review summarise the transfer hydrogenation of C=O, C=C, C=N bonds of unsaturated substrates via Cp*Ir complexes as catalysts and formic acid/formate as hydrogen sources.

Double Catalytic Activity Unveiled: Synthesis, Characterization, and Catalytic Applications of Iridium Complexes in Transfer Hydrogenation and Photomediated Transformations

“…Transfer hydrogenation from formic acid was also successful (Scheme , conditions B) . In general, slightly lower yields were obtained when compared to the reaction with 2-propanol (Scheme , 23 , 25 , 27 , and 32 ).…”

“…Transfer hydrogenation from formic acid was also successful (Scheme 7, conditions B). 48 In general, slightly lower yields were obtained when compared to the reaction with 2-propanol (Scheme 7, 23, 25, 27, and 32). However, the reaction worked better with 4′-methoxyacetophenone (8) and 4′-bromoacetophenone (13), affording the corresponding alcohols, 28 and 30, in 43 and 90% yield, respectively.…”

Construction of N-Aryl-Substituted Pyrrolidines by Successive Reductive Amination of Diketones via Transfer Hydrogenation

“…In this context, hydrogen donors such as formic acid were widely utilized in differential transfer hydrogenation reactions owing to their potential hydrogen storage, low toxicity, as well as ease of handling [ 48 ]. We have great interest in transfer hydrogenation and conducted a series of relative studies using iridium complexes as catalysts [ 49 ], by which reduction in unsaturated compounds [ 50 , 51 ], silane oxidation [ 52 ], N -allylic alkylation [ 53 ], reductive amination [ 54 ], reductive amination [ 55 ], as well as reductive etherification [ 56 ] were reported. Recently, we established a one-pot procedure for synthesizing amines via reduction-reductive amination ( Scheme 2 a) [ 57 ].…”

A ratiometric substrate for rapid evaluation of transfer hydrogenation efficiency in solution

“…Our strategy relies on the use of a ratiometric substrate that allows in situ quantification of the reaction progress. 18,19 This approach enables simultaneous monitoring of multiple reactions using minimum amounts of sample, which is particularly attractive for studies of catalysts that are costly (e.g., those containing Ir, 20 Ru, 21 or Os 22 ) or difficult to obtain on large scales.…”