This tutorial review describes recent progress in the development of homogeneous catalytic methodology for the direct generation of hydrogen gas from formic acid and alcohols.

Original citation:Johnson, Tarn C., Totty, William and Wills, Martin. (2012) Application of ruthenium complexes of triazole-containing tridentate ligands to asymmetric transfer hydrogenation of ketones. Organic Letters, 14 (20). pp. 5230-5233. Permanent WRAP url:http://wrap.warwick.ac.uk/55213 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:This document is the Accepted Manuscript version of a Published Work that appeared in final form in Organic Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work, see http://dx.doi.org/10.1021/ol302354z A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. For more information, please contact the WRAP Received Date (will be automatically inserted after manuscript is accepted) ABSTRACTThe synthesis of a series of tridentate ligands based on a homochiral 1,2-diamine structure attached to a triazole group, and their subsequent applications to the asymmetric transfer hydrogenation of ketones, are described. In the best cases, alcohols of up to 93% ee were obtained. Although base is not required, the use of Ru3(CO)12 as metal source is essential, indicating a unique mechanism for the formation of the active catalyst.

A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. For more information, please contact the WRAP ABSTRACT A series of (cyclopendienone)irontricarbonyl complexes were prepared using an intramolecular cyclisation strategy. These were applied to the catalysis of the oxidation of alcohols to aldehydes and ketones. When paraformaldehyde was used as the hydrogen acceptor, formate esters were obtained as co-products and, in several cases, the major products.

The preparation of a range of asymmetric iron and ruthenium-cyclone complexes, and their application to the asymmetric reduction of a ketone, are described. The enantioselectivity of of ketones reduction is influenced by a single chiral centre in the catalyst, as well as by the planar chirality in the catalyst. This represents the first example of asymmetric ketone reduction using an iron cyclone catalyst. Introduction 10The ruthenium complex 1 (the Shvo catalyst)1-4 reversibly splits to give hydride 2 and the unsaturated species 3.15 By 'shuttling' between 2 and 3, the Shvo catalyst transfers pairs of hydrogen atoms between secondary alcohols and ketones and has been used to good effect in dynamic kinetic resolution (DKR) reactions of alcohols and amines.2,3 There is evidence, 4 largely based on kinetic isotope effects, that the 20 hydrogen transfer to ketones and aldehydes, by the Shvo catlyst, takes place via a concerted 'outer sphere' mechanism ( Figure 1a). This is analogous to that of of ketone reduction by the Noyori catalyst 4 (Figure 1b). The Shvo catalyst is also an efficient ketone reducing agent when using an excess of an alcohol (usually iPrOH) or formic acid as hydrogen source, 1d and can also catalyse hydrogenation reactions. 1b,c,4d,6 The closely related iron complex 5 has recently been prepared from the tricarbonyl 35 precursor 6 7 and employed in catalytic reduction reactions of ketones by Casey and Guan.8 The mechanism appears to be analogous to that of the Shvo catalyst 2 (Figure 1c). In recent studies, complex 5 has been applied to the oxidation of alcohols using acetone as an acceptor, and a number of its 40 derivatives have been reported and evaluated in this role. 9 In our own studies, 10 we reported the synthesis and applications of racemic complexes 7a-7g in alcohol oxidations. The complexes were formed by an intramolecular cyclisation from a linear dialkyne precursor 8, followed by diastereoisomer 45 separation. 7,1150

Visible light photocatalysis allows the introduction of the sulfone functional group to anilines under mild reaction conditions, without the need for pre-functionalization.

Heteroaromatic nitriles are important compounds in drug discovery, both for their prevalence in the clinic and due to the diverse range of transformations they can undergo. As such, efficient and reliable methods to access them have the potential for far‐reaching impact across synthetic chemistry and the biomedical sciences. Herein, we report an approach to heteroaromatic C−H cyanation through triflic anhydride activation, nucleophilic addition of cyanide, followed by elimination of trifluoromethanesulfinate to regenerate the cyanated heteroaromatic ring. This one‐pot protocol is simple to perform, is applicable to a broad range of decorated 6‐ring N‐containing heterocycles, and has been shown to be suitable for late‐stage functionalization of complex drug‐like architectures.

A one-pot, three-component synthesis of αpyridyl, α-substituted amino acid derivatives is described. The key transformation is a direct, precious-metal-free heteroarylation of readily available, amino acid derived azlactones with electrophilically activated pyridine N-oxides. The resulting intermediates can be used directly as efficient acylating agents for a range of nucleophiles, leading to the heteroarylated amino acid derivatives in a single vessel.

SummaryA convenient, one-pot, two-component synthesis of 2-(1-amidoalkyl)pyridines is reported, based upon the substitution of suitably-activated pyridine N-oxides by azlactone nucleophiles, followed by decarboxylative azlactone ring-opening. The synthesis obviates the need for precious metal catalysts to achieve a formal enolate arylation reaction, and constitutes a formally ‘umpoled’ approach to this valuable class of bioactive structures.