Rhodium acetamide

Gil ED, Kubota LT (2000) Electrochemical behavior of rhodium acetamidate immobilized on a carbon paste electrode a hydrazine sensor. J Braz Chem Soc 11 304—310... 

Other compounds with the lantern structure include the acetamidates Rh2(MeCONH)4L2 and the mixed-valence anilinopyridinate Rh2(ap)4Cl (Figure 2.39), which has an unusual ESR spectrum in that the electron is localized on one rhodium [79]. 

Based on their unique stereochemistry in which two nitrogens and two oxygens are bound to each rhodium in a ris-2,2 fashion, dirhodium(II) car-boxamidates, exemplified by dirhodium(II) acetamidate [Rh2(acam)4],... 

Rhodium(II) acetamide, Rh,(NHCOCH,)4 (1). The reagent is obtained by reaction of Rh,(OAc)4 with molten acetamide. It crystallizes from water as a hydrate.1... 

Stereoselective inns-cyclopropanation. Rhodium(II) carboxylates are generally the preferred catalysts for cyclopropanation of alkenes with diazoacetates (7,313 9,406,10,340) even though they show only low tram-selectivity. The tram-selectivity can be markedly enhanced by use of rhodium(II) acetamide. Use of rhodium(II) 2,4,6-triarylbenzoates favors ds-stereoselectivity.1... 

Hydration of nitriles providing carboxamides is usually carried out m strongly basic or acidic aqueous media - these reactions require rather bars conditions and suffer from incomplete selectivity to the desired amide product. A few papers in the literature deal with the possibihty of transition metal catalysis of this reaction [28-30]. According to a recent report [30], acetonitrile can be hydrated into acetamide with water-soluble rhodium(I) complexes (such as the one obtained from [ RhCl(COD) 2] and TPPTS) under reasonably mild conditions with unprecedently high rate... 

Figure 8.10 Conversions (%) (top) and ees (bottom) obtained in the rhodium-catalyzed hydrogenation of N-(3,4-dihydro-naphthalen-2-yl)acetamide upon applying various SUPRAphos ligands.

Considerable variation in stereocontrol can also occur, depending on the catalyst employed (equation 125). In general, the various rhodium(II) carboxylates and palladium catalysts show little stereocontrol in intermolecular cyclopropanation162,175. Rhodium(II) acetamides and copper catalysts favour the formation of more stable trans (anti) cyclopropanes162166. The ruthenium bis(oxazolinyl)pyridine catalyst [Ru(pybox-ip)] provides extremely high trans selectivity in the cyclopropanation of styrene with ethyl diazoacetate43. Furthermore, rhodium or osmium porphyrin complexes 140 are selective catalysts... 

A regioselective hydroformylation-amidocarbonylation process of a fluoroolefin is reported for cobalt-rhodium bimetallic catalyst systems With Rh6(CO),6 and Co2(CO)8 (1 50) in dioxane, 3,3,3-trifluoropropene (57) reacts with acetamide under hydroformylation conditions to give 58 with 94% selectivity (80-bar CO, 50-bar H2, 120°C, 10 hr, CT821) (226,275) ... 

The application of a mixture of a chiral and an achiral monophosphorus ligand for the rhodium catalyzed asymmetric hydrogenation of enamides was tested by Beller and coworkers [45]. By using a mixture of a chiral monophosphine 36a and an achiral ligand tris(4 methoxyphenyl)phosphine [P(4 MeOCf,H4)3] (1 1), the N (1 phenylvi nyl)acetamide (7a) was hydrogenated to amine 8a with 88% ee, but this enantios electivity is inferior to that obtained with single monophosphine 36a (93% ee). 

Rhodium(III)-promoted intramolecular hydroarylation or amidoarylation of iV- 3-[(but-3-yn-l-yl)oxy]phenyl acetamides are conditions-controUable to afford chromans or heterocyclic-fiised chromans,respectively (14CC7306). A different rhodium catalyst was applied to the synthesis of ring-fused chromans through decarbonylative alkyne insertion of 2-[(but-3-yn-l-yl)oxy] benzo cyclobutanones (Scheme 29) (14AGE1674). 

In general the reduction of a pyridine side-chain acid or ester using platinum oxide, Raney Nickel, rhodium-on-carbon, rhodium-on-alumina, or ruthenium oxide as the catalyst gives the piperidine acid or ester. Partial reduction of the pyridine ring to a tetrahydropyridine usually occurred when palladium-on-carbon was employed as the catalyst, although two exceptions were reported. Either a mixture of the piperidine and the tetrahydropyridine ester or the tetrahydropyridine ester alone was formed when sodium borohydride was used at room temperature in the reduction of pyridine side-chain ester salts. When the free bases were employed, reduction of the ester group occurred instead of nuclear reduction. The use of lithium aluminum hydride gave the same results (see Table XI-18). Many acetamides... 

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