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The cyclic hydroxamic acid functional group is critical to the biological activity of numerous natural products and drug candidates. Efficient, reliable, and green synthetic methods to produce cyclic hydroxamic acids are needed. Herein, flow hydrogenation has been explored as a novel approach toward achieving the selective partial reduction of 2-nitrophenylacetic acid to 1-hydroxyindolin-2-one. The bidentate ligand, 1,10-phenanthroline, has been identified as a unique inhibitor for modulating product selectivity in this Pt/C-catalyzed process. Under the newly optimized reaction conditions, the targeted hydroxami c acid is produced with high selectivity (49:1) over the lactam by-product. The scope of the reaction is demonstrated for a variety of 2-nitrophenylacetic acid derivatives. [ABSTRACT FROM AUTHOR]

The chemoselectivity of hydrodechlorination in 2-chloropyridine derivatives possessing reduction-sensitive functionalities is examined. The reaction conditions employed tolerate a variety of functionalities illustrating highly chemoselective hydrodechlorination in the presence of nitrile, allyl, terminal olefin, and nitroamine functionalities in excellent yield. Chemoselective deprotection of carboxybenzyl ethers is illustrated in moderate yield. [ABSTRACT FROM AUTHOR]

Abstract: Treatment of halogen-heteroaromatic aldehydes with catalytic amount of PdCl2 under atmosphere pressure of hydrogen in base medium (sodium acetate) leads to the corresponding dehalogenated primary alcohols. The reaction system was especially effective for the heteroaromatic compounds bearing aldehyde groups and halides (bromo- or chloro-functions). [Copyright &y& Elsevier]

Abstract: A simple and electrolyte-free ion-transfer electrosynthesis micro-reactor system (volume 100μL, up to 10mg batches) for processes at liquid–liquid interfaces is developed and demonstrated for the reduction of aldehydes and imines. These cathodic reactions occur at an amphiphilic carbon nanofiber membrane accompanied by proton cation transfer from an aqueous phase into an organic phase. [Copyright &y& Elsevier]

Abstract: The total synthesis of Resolvin E2, an endogenous lipid mediator of the resolution of inflammation derived from eicosapentaenoic acid, has been achieved. The chiral hydroxy-groups at C5 and C18 were generated in a simple, efficient, and environmentally friendly manner via an asymmetric Noyori transfer hydrogenation in water using sodium formate as a reducing agent. Pd0/CuI Sonogashira couplings of the three key fragments and Zn(Cu/Ag) reduction completed the synthesis of Resolvin E2. [Copyright &y& Elsevier]

Abstract: Secondary amides undergo in situ silyl imidate formation mediated by TMSOTf and an amine base, followed by addition to acetal acceptors to provide N-acyl-N,O-acetals in good yields. An analogous, high-yielding reaction is observed with 2-mercaptothiazoline as the silyl imidate precursor. Competing reduction of the acetal to the corresponding methyl ether via transfer hydrogenation can be circumvented by the replacement of CY2NMe with 2,6-lutidine under otherwise identical reaction conditions. [Copyright &y& Elsevier]

Abstract: A ruthenium catalyst formed in situ by combining [Ru(p-cymene)Cl2]2 and an amino acid hydroxy-amide was found to catalyze efficiently the asymmetric reduction of aryl alkyl ketones under transfer hydrogenation conditions using ethanol as the hydrogen donor. The secondary alcohol products were obtained in moderate to good yields and with good to excellent enantioselectivity (up to 97% ee). [Copyright &y& Elsevier]

Abstract: The reduction of allyl aryl ethers using sodium borohydride in the presence of a catalytic amount of ruthenium(III) chloride in various aqueous solvent mixtures at 0°C was examined. In aqueous tetrahydrofuran, hydrogenation was the favored pathway (85–100% yield of the corresponding aryl propyl ether); whereas in aqueous N-methylformamide, reductive cleavage predominated (4:1 mixture of phenolic product/aryl propyl ether). In order to gain some insight into the mechanism for this process, 3-octyn-1-ol and trans-2-decen-1-yl acetate were subjected to similar reductive conditions; and both substrates afforded products inconsistent with a single-electron-transfer mechanism. [ABSTRACT FROM AUTHOR]

Abstract: A novel application of silver(I) salt promoters in silver- and gold-catalysed hydrogenations was applied to the chemoselective reduction of halonitrobenzenes resulting in excellent conversions and selectivities. This reactivity, coupled with the low cost of silver relative to more expensive precious metal counterparts, demonstrates this catalytic system as an attractive alternative for challenging chemoselective transformations. [ABSTRACT FROM AUTHOR]

Abstract: A method for the rapid, safe reduction of heteroaromatic and aromatic nitro groups to amines is described using catalytic transfer hydrogenation under microwave heating conditions. Commonly available Pd/C or Pt/C catalyst is extremely effective with 1,4-cyclohexadiene as the hydrogen transfer source. In the case of substrates containing potentially labile aromatic halogens, Pt/C is effective and results in little or no dehalogenation. In general, the reactions are complete within 5min at 120°C. [Copyright &y& Elsevier]

A practical direct reductive amination reaction of aldehydes in aqueous sodium formate solution which produces amines in good yields under mild conditions is described. The amount and strength of the acid additives were critical factors to affect the reaction selectivities. This reductive amination method has great application potential for the synthesis of amine products given the mild conditions, short reaction time, the use of water as a solvent, and the use of benign hydrogen sources. [ABSTRACT FROM AUTHOR]

Abstract: A chemoselective and highly efficient hydrogenation of nitroarenes and deoxygenation of pyridine N-oxides using a cheap and environmentally friendly H2/MoO2Cl2 system has been developed [Copyright &y& Elsevier]

Abstract: As an efficient catalyst for asymmetric transfer hydrogenation reaction (ATH reaction) of α,β-unsaturated ketones, Rh-Cp∗–TsDPEN (Cp∗ =1,2,3,4,5-pentamethylcyclopenta-1,3-diene, TsDPEN= N-(p-toluenesulfonyl)-1,2-diphenyl- ethylenediamine) shows high chemoselectivity on Ce:glyph name="dbnd" />C reduction. In our method, both Ce:glyph name="dbnd" />C bonds in a variety of chromenone derivatives were reduced efficiently in aqueous media, resulting in at least 98% ee and up to 99% yields in a convenient way without further purification. The product was a useful intermediate for deriving chiral chroman-4-amine, which was reported as an effective agent against hypotension and inflammatory pain by inhibiting human bradykinin B1 receptor. [Copyright &y& Elsevier]

Abstract: A novel method of hydrogenation of aromatic ketones in the ionic liquid [BHEA][HCO2] was developed; this method is more enhanced in terms of flammability and reusability as compared to the conventional method (H2 and Pd/C). The reductive selectivities of aromatic and aliphatic ketones in this method were observed. [Copyright &y& Elsevier]

Abstract: An efficient, easy, cheap, convenient, and safe procedure for the reduction of various alkenes to the corresponding alkanes is developed by using scrap automobile catalyst as an efficient hydrogenation catalyst. This procedure not only gives high yields, but also allows recycling of automobile wastes as a catalyst in organic reactions and is representative of green chemistry. [Copyright &y& Elsevier]

Abstract: Various ketones were efficiently transformed into the corresponding amines using ammonium formate in the presence of Zn dust or 10% Pd/C. The low-cost Zn dust method proved to be effective in amine formation from carbonyl groups at the benzylic side-chain position of aromatic systems, whereas 10% Pd/C was an efficient catalyst in the reductive aminations of carbonyl groups non-conjugated with any π-system. The 10% Pd/C-catalyzed reductions were performed more effectively in a continuous-flow X-Cube reactor than in the batch system. [Copyright &y& Elsevier]

Abstract: Some achiral β-amino alcohols have been shown as efficient ligands for the ruthenium-catalysed asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)imines in isopropanol. The ruthenium complex prepared from [RuCl2(p-cymene)]2 (2.5mol%) and 2-amino-2-methyl-1-propanol (5mol%) leads to α-branched chiral primary amines with very high optical purities (up to 98% ee) by the diastereoselective reduction of the imines followed by removal of the sulfinyl group under mild acidic conditions. Short reaction times (2–3h) were needed to complete the reduction reactions when they were performed at 50°C. [ABSTRACT FROM AUTHOR]

Abstract: A simple and efficient deuteration methodology has been established for a wide variety of substrates using a continuous flow hydrogenation reactor. The described procedure is many times faster (1mgmin−1) compared to literature methods and the purity of the crude product can be as high as 99%. The deuterium source is D2O, the consumption of which is very low. [Copyright &y& Elsevier]

Abstract: Easily accessible in situ catalysts composed of [Ru(cod)(2-methylallyl)2] and N-heterocyclic carbene ligands have been developed for the environmentally benign hydrogenation of various nitriles to give primary amines. Applying optimized conditions in the presence of SIMesBF4 as ligand high catalyst activity of up to 392h−1 is achieved in the hydrogenation of benzonitrile. The general applicability and functional group tolerance of this novel catalyst system are shown in the reduction of ten different nitriles. [Copyright &y& Elsevier]

Abstract: Hydrogen transfer reduction of α-sulfonylaldehydes using HCOOH–Et3N system as hydrogen source and (S,S)-TsDPEN-based Ru(II) as catalyst proceeds with dynamic kinetic resolution, providing optically active β-sulfonyl primary alcohols in moderate-to-good yields and up to 90% ee. [Copyright &y& Elsevier]

Two practical catalytic asymmetric reductions to introduce the epothilone C15 stereocenter are described (Itsuno–Corey reduction and Noyori hydrogenation). [Copyright &y& Elsevier]