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Hydrogen Transfer Reactions: Reductions and Beyond by Gabriela Guillena, Diego J. Ramón

By Gabriela Guillena, Diego J. Ramón

The sequence themes in present Chemistry Collections provides serious experiences from the magazine issues in present Chemistry geared up in topical volumes. The scope of assurance is all parts of chemical technology together with the interfaces with similar disciplines resembling biology, medication and fabrics technology. The objective of every thematic quantity is to provide the non-specialist reader, no matter if in academia or undefined, a complete perception into a space the place new examine is rising that's of curiosity to a bigger clinical audience.
each one evaluation in the quantity significantly surveys one element of that subject and areas it in the context of the amount as an entire. the main major advancements of the final five to ten years are offered utilizing chosen examples to demonstrate the foundations mentioned. The insurance isn't really meant to be an exhaustive precis of the sphere or contain huge amounts of knowledge, yet may still otherwise be conceptual, focusing on the methodological considering that would enable the non-specialist reader to appreciate the data offered. Contributions additionally provide an outlook on power destiny advancements within the field.

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52) were designed based on detailed mechanistic investigations and investigations into the nature of the base activation of iron(II) carbonyl complexes of the second generation [146, 147], affording even more reactive catalytic species [148–150]. The ATH of (hetero)aryl ketones applying complexes 170–172 gave moderate to high enantioselectivities (24–98 % ee) with TOF as high as 242 s-1. The precatalyst 171, with para-tolyl substituent on a phosphorus donor, gave the highest TOF of 152 s-1 in reducing acetophenone, while the complex 172 displayed the best enantioselectivity (90 % ee; Fig.

The catalyst 139 prepared by a cocondensation strategy (immobilisation of Cp*RhTsDPEN functionalities within the silicate network forming uniformly distributed active species) presented a slightly higher catalytic efficiency than catalyst 138 derived from a postmodification method (the log-jam of Cp*RhTsDPEN functionalities near the nanopore mouth results in a disorderly distribution of active species) suggesting that the distribution of active centres plays an important role in enantioselective performance.

While ferrocenyl-phosphine ligands work well in metal-catalysed ATH, the analogous phosphinites can provide different chemical, electronic and structural properties due to an often stronger metal-phosphorous bond if compared to related phosphines. In this regard, the phosphinite ligands based on the ferrocenyl moiety containing a stereogenic centre have been screened in Ru(II)-catalysed ATH of aromatic ketones with propan-2-ol as the hydrogen source [86]. While the reduction of acetophenone in the presence of the complex [Ru(II)–93] and applying S/C/ NaOH 100:1:5 was sluggish at room temperature, it was enormously accelerated in refluxing propan-2-ol, thus reaching nearly quantitative conversion and a 95 % ee in 20 min.

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