Iron–PNP‐Pincer‐Catalyzed Transfer Dehydrogenation of Secondary Alcohols

Abstract

What was the inspiration for this cover design?The image shows the forging of ah orseshoe. In our work, the horseshoe represents an iron-based pincerc atalyst that can be conveniently appliedi nt he dehydrogenation of secondary alcohols. The backbone of the PNP-pincer ligand possesses the same shape as the pictured horseshoe, and furthermore, the iron metal centeri sr epresented here as the main component of as teel horseshoe. The mild oxidation requires the presence of acetonea sahydrogen acceptor, whichi ss ymbolized by the stroke of ahammer.

Sugars as Novel, Effective, and Renewable Hydrogen Sources in Dehydrogenation and Catalytic Transfer Hydrogenation Reactions

“…When α-D-glucose was used, a full conversion of 4-fluorobenzadehyde was obtained after 16 h ( 19 F NMR spectroscopy, Figure 4). As expected, the 13 C NMR spectrum consisted of the characteristic signal at δ ¼ 176 ppm, indicating the formation of D-gluconopyranolactone. It is worth noting that side reactions such as the competitive self-hydrogenation of glucose to sorbitol were not observed from this reaction.…”

“…[ 12 ] An attractive feature of this process is that it can be accomplished under mild reaction conditions where the operating temperature is typically less than 200 °C. [ 13 ] Catalytic dehydrogenation at room temperature (RT) has also been demonstrated. [ 14 ]…”

“…From the 13 C NMR spectrum described earlier, it is apparent that α-D-glucose was dehydrogenated not only effectively but also regioselectively by ss1. Only the OH group and the hydrogen atom bonded to the anomeric C 1 carbon participated in the dehydrogenation reaction.…”

“…[11] Alternatively, liquid "hydrogen donors" such as alcohols and formic acid have been proven as excellent sources of hydrogen gas through catalytic dehydrogenation (Scheme 1). [12] An attractive feature of this process is that it can be accomplished under mild reaction conditions where the operating temperature is typically less than 200 C. [13] Catalytic dehydrogenation at room temperature (RT) has also been demonstrated. [14] Despite advances in hydrogen production, one major disadvantage of the current processes lies in the dependence of nonrenewable fossil fuel sources.…”

Synthesis and Reactivity of titanium ‘POCOP’ pincer complexes

“…Since their initial discovery by Shaw in 1976 pincer complexes have held a privileged position in organometallic chemistry. [1][2][3] Pincer complexes are widely applied in catalysis for example in iron catalysed hydrogenations, [4][5][6][7][8][9][10][11][12][13] iridium and ruthenium catalysed alkane dehydrogenation, [14][15][16][17][18][19][20][21][22][23][24][25][26][27] and cross-coupling reactivity. [28][29][30][31][32][33][34][35][36][37][38] Pincer ligands also support interesting reactivity, for example acting as a two-electron sink to augment reactivity.…”