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trans-Dichloropalladium(II) complexes with amino acid esters PdCl2L2 have been synthesized via selective hydrolytic cleavage of the nitrogen–carbon bond in 1,3,5-tris(ethoxycarbonylmethyl)- and 1,3,5-tris[(S)-1′(methoxycarbonyl)ethyl]-1,3,5-triazinane under the action of palladium(II) in methanol or in water–acetone mixture. The nucleophilic attack of water or methanol results in selective cleavage of the 1,3,5-triazinane ring in the complexes of palladium(II) with the starting triazinanes, affording the dichloropalladium(II) complexes with amino acids esters.

Luzopeptins and related decadepsipeptides are bisintercalator nonribosomal peptides featuring rare acyl-substituted tetrahydropyridazine-3-carboxylic acid (Thp) subunits that are critical to their biological activities. Herein, we reconstitute the biosynthetic tailoring pathway in luzopeptin A biosynthesis through in vivo genetic and in vitro biochemical approaches. Significantly, we revealed a multitasking cytochrome P450 enzyme that catalyzes four consecutive oxidations including the highly unusual carbon-nitrogen bond desaturation, forming the hydrazone-bearing 4-OH-Thp residues. Moreover, we identified a membrane-bound acyltransferase that likely mediates the subsequent O-acetylation extracellularly, as a potential self-protective strategy for the producer strain. Further genome mining of novel decadepsipeptides and an associated P450 enzyme have provided mechanistic insights into the P450-mediated carbon-nitrogen bond desaturation. Our results not only reveal the molecular basis of pharmacophore formation in bisintercalator decadepsipeptides, but also expand the catalytic versatility of P450 family enzymes.

A green reaction medium has been developed from the Water Extract of Teak leaf (Tectona grandis) ash (WET). The alkaline nature of the WET was successfully applied towards hydration of nitriles, conversion of arylboronic acids to phenols with 30% aqueous H2O2, Knoevenagel condensation for benzylidenemalononitrile derivatives formation and Chan-Lam reaction of arylboronic acids with imidazole derivatives. In current protocols dual role of WET as reaction medium as well as base has been explored. A wide range of substrates with varying electronic natures is compatible under these WET mediated reaction conditions with excellent yields.

An efficient strategy is developed for chemical recycling of cured epoxy resin (CEP) from its carbon fiber reinforced polymer composites (CFREP) using AlCl3/CH3COOH as the degradation system. Acetic acid swells the dense structures of CEP, facilitating the penetration of the aluminum ion catalyst into the polymer matrix. The weakly coordinating aluminum ions in CH3COOH solution selectively cleave the C–N bond while leaving the C–C, C–O (aryl alkyl ether) bonds intact. This process recovers valuable oligomers and carbon fibers from CFREP.

New carbon-nitrogen bonds were formed on addition of isocyanide and ketone reagents to the oxonitride species [{Ti(η(5)-C5Me5)(μ-O)}3(μ3-N)] (1). Reaction of 1 with XylNC (Xyl = 2,6-Me2C6H3) in a 1:3 molar ratio at room temperature leads to compound [{Ti(η(5)-C5Me5)(μ-O)}3(μ-XylNCCNXyl)(NCNXyl)] (2), after the addition of the nitrido group to one coordinated isocyanide and the carbon-carbon coupling of the other two isocyanide molecules have taken place. Thermolysis of 2 gives [{Ti(η(5)-C5Me5)(μ-O)}3(XylNCNXyl)(CN)] (3) where the heterocumulene [XylNCCNXyl] moiety and the carbodiimido [NCNXyl] fragment in 2 have undergone net transformations. Similarly, tert-butyl isocyanide (tBuNC) reacts with the starting material 1 under mild conditions to give the paramagnetic derivative [{Ti3(η(5)-C5Me5)3(μ-O)3(NCNtBu)}2(μ-CN)2] (4). However, compound 1 provides the oxo ketimide derivatives [{Ti3(η(5)-C5Me5)3(μ-O)4}(NCRPh)] [R = Ph (5), p-Me(C6H4) (6), o-Me(C6H4) (7)] upon reaction with benzophenone, p-methylbenzophenone, and o-methylbenzophenone, respectively. In these reactions, the carbon-oxygen double bond is completely ruptured, leading to the formation of a carbon-nitrogen and two metal-oxygen bonds. The molecular structures of complexes 2-4, 6, and 7 were determined by single-crystal X-ray diffraction analyses. Density functional theory calculations were performed on the incorporation of isocyanides and ketones to the model complex [{Ti(η(5)-C5H5)(μ-O)}3(μ3-N)] (1H). The mechanism involves the coordination of the substrates to one of the titanium metal centers, followed by an isomerization to place those substrates cis with respect to the apical nitrogen of 1H, where carbon-nitrogen bond formation occurs with a low-energy barrier. In the case of aryl isocyanides, the resulting complex incorporates additional isocyanide molecules leading to a carbon-carbon coupling. With ketones, the high oxophilicity of titanium promotes the unusual total cleavage of the carbon-oxygen double bond.

The carbon-nitrogen bond of β-lactams is cleaved by palladium(0), and an alkene is intramolecularly inserted therein. The following reductive elimination produces nitrogen-containing benzo-fused tricycles in good to high yields.

Over the past few decades, researchers have made substantial progress in the development of transition metal complexes that activate and functionalize C-H bonds. For the most part, chemists have focused on aliphatic and aromatic C-H bonds and have put less effort into complexes that activate and functionalize vinylic C-H bonds. Our groups have recently developed a novel method to functionalize vinylic C-H bonds that takes advantage of the unique ligand-based reactivity of a rare class of metal dinitrosyl complexes. In this Account, we compare and discuss the chemistry of cobalt and ruthenium dinitrosyl complexes, emphasizing alkene binding, C-H functionalization, and catalysis. Initially discovered in the early 1970s by Brunner and studied more extensively in the 1980s by the Bergman group, the cyclopentadienylcobalt dinitrosyl complex CpCo(NO)2 reacts reversibly with alkenes to give, in many cases, stable and isolable cobalt dinitrosoalkane complexes. More recently, we found that treatment with strong bases, such as lithium hexamethyldisilazide, Verkade's base, and phosphazene bases, deprotonates these complexes and renders them nucleophilic at the carbon α to the nitroso group. This conjugate anion of metal dinitrosoalkanes can participate in conjugate addition to Michael acceptors to form new carbon-carbon bonds. These functionalized cobalt complexes can further react through alkene exchange to furnish the overall vinylic C-H functionalized organic product. This stepwise sequence of alkene binding, functionalization, and retrocycloaddition represents an overall vinylic C-H functionalization reaction of simple alkenes and does not require directing groups. We have also developed an asymmetric variant of this reaction sequence and have used this method to synthesize C1- and C2-symmetric diene ligands with high enantioinduction. Building upon these stepwise reactions, we eventually developed a simple one-pot procedure that uses stoichiometric amounts of a cobalt dinitrosoalkane complex for both inter- and intramolecular C-H functionalization. We can achieve catalysis in one-pot intramolecular reactions with a limited range of substrates. Our groups have also reported an analogous ruthenium dinitrosyl complex. In analogy to the cobalt complex, this ruthenium complex reacts with alkenes in the presence of neutral bidentate ligands, such as TMEDA, to give octahedral dinitrosoalkane complexes. Intramolecular functionalization or cyclization of numerous ruthenium dinitrosoalkane complexes proceeds under mild reaction conditions to give the functionalized organic products in excellent yields. However, despite extensive efforts, so far we have not been able to carry out intermolecular reactions of these complexes with a variety of electrophiles or C-H functionalization reactions. Although additional work is necessary to further boost the catalytic capabilities of both cobalt and ruthenium dinitrosyl complexes for vinylic C-H functionalization of simple alkenes, we believe this ligand-based vinylic C-H functionalization reaction has provided chemists with a useful set of tools for organic synthesis.

The first Negishi cross-coupling of amides for the synthesis of versatile diaryl ketones by selective C−N bond activation under exceedingly mild conditions is reported. The cross-coupling was accomplished with bench-stable, inexpensive precatalyst [Ni(PPh3)2Cl2] that shows high functional-group tolerance and enables the synthesis of highly functionalized diaryl ketone motifs. The coupling occurred with excellent chemoselectivity favoring the ketone (cf. biaryl) products. Notably, this process represents the mildest conditions for amide N−C bond activation accomplished to date (room temperature

The metal coordination complex K4[Fe(CN)6] is an efficient and environmentally benign catalyst for the synthesis of imidazolines and benzimidazoles from various aldehydes and 1,2-diamines in aqueous medium at room temperature. This protocol gives excellent yield of product with desired purity.

Heating [WO 2 (S 2 CNBu i 2 ) 2 ] with a slight excess of ArNCO (Ar = Ph, p-tolyl) results in the rapid formation of imido-ureato complexes [W(NAr){κ 2 -ArNC(O)NAr}(S 2 CNBu i 2 ) 2 ], a transformation believed to occur via the bis(imido) intermediates [W(NAr) 2 (S 2 CNBu i 2 ) 2 ]. The ureato ligand is easily removed (as the urea) upon addition of gaseous HCl to afford the dichloride [W(NAr)Cl 2 (S 2 CNBu i 2 ) 2 ]. While bis(imido) complexes are unavailable from the direct reaction of isocyanates (or amines) with [WO 2 (S 2 CNBu i 2 ) 2 ], they can be prepared upon addition of dithiocarbamate salts to [W(NBu t ) 2 (NHBu t ) 2 ] addition of two equivalents of [NH 2 Bu i 2 ][Bu i 2 NCS 2 ] affording [W(NBu t ) 2 (S 2 CNBu i 2 ) 2 ] in which both imido groups are linear.

Carbon–nitrogen bond activation of amines by rhodium porphyrin chloride has been achieved to give rhodium porphyrin alkyl complexes. Rhodium porphyrin hydride and rhodium porphyrin dimer were proposed as the intermediates in cleaving the C–N bond.

The carbon–nitrogen bond of β-lactams is cleaved by palladium(0), and an alkene is intramolecularly inserted therein. The following reductive elimination produces nitrogen-containing benzo-fused tricycles in good to high yields.

Formation of carbon–nitrogen bond in ball-milling conditions was effected in numerous chemical transformations, with formation of important nitrogen-containing compounds, such as imines, amides, (thio)ureas, oximes, hydrazones, and nitrones. Most prominent is the preparation of amide (peptide) bond. Different nitrogen-containing heterocycles (phenazines, quinazolinones, pyrazolines, pyrazoles, thiazolidines, benzothiazoles, benzimidazoles, benzoxazoles, and indoles) were prepared mechanochemically, often via multistep reactions.

Gone fishing: When propiophenone and related ethyl ketones are treated with morpholine in the presence of K(3)PO(4), chlorobenzene, and [Ni(cod)(2)]/PMe(3) catalyst, a carbon-nitrogen bond is formed selectively at the beta position (see scheme; cod = cycloocta-1,5-diene). Secondary amines were employed as substrates to give the corresponding beta-enaminones.

The reactivity of a series of amines with various structures and different numbers of hydrogen atoms on the carbon atoms in the α and β position, with respect to the nitrogen atom, was examined on four transition metal sulfides, i.e. NbS3, MoS2, RuS2, and Rh2S3. It is shown that the reaction mechanism proceeds via an elimination or a nucleophilic substitution the relative importance of which depends on the structure of the substrate to be transformed and on the transition metal sulfides properties. NbS3is the most active sulfide of the series for the elimination reaction due to its high acidity, but it is inactive for the nucleophilic substitution. On the other hand, the surface species of Rh2S3can be involved in a nucleophilic substitution but not in an elimination reaction. The other sulfides of the series behave in between. These results clearly demonstrate that the catalysts intervene differently in the HDN mechanism. Moreover, for a given solid the structure of a nitrogen-containing molecule strongly affects the elementary steps of its transformation. Accordingly, a precise mechanistic study of the reactivity of a model molecule at the surface of a sulfide cannot be generalized to the overall HDN process which involves several types of molecules.

A series of monomeric palladium amido complexes of the form trans-(PPh3)2Pd(Ar)(NAr‘2) and (DPPF)Pd(Ar)(NAr‘2) (DPPF = 1,1‘-bis(diphenylphosphino)ferrocene) and dimeric palladium amido complexes of the form {(PPh3)Pd(Ar)(μ-NHR)}2 (R = Ph, t-Bu) have been prepared by the reaction of lithium and potassium amides with palladium aryl halide complexes. An X-ray crystal structure of (DPPF)Pd(p-NMe2C6H4)[N(p-CH3C6H4)2] was obtained. Upon thermolysis in the presence of PPh3, serving as a trapping agent, both the monomeric and dimeric palladium amido complexes underwent C−N-bond-forming reductive elimination to form arylamines in high yields along with a Pd(0) species. Reductive elimination was also observed from azametallacycle (PPh3)Pd(η2-C6H4C6H4NH), to form carbazole and Pd(PPh3)4 at room temperature. Mechanistic studies on the reductive elimination reactions of the monomeric PPh3-ligated amido complexes indicated the presence of two competing pathways for the formation of amine. At low [PPh3], reductive elimi...

The reaction of the {eta}{sup 2}(N,C)-pyridine complex with LiBEt{sub 3}H affords the C-N bond scission product (2). The reactions of (1) with carbon nucleophiles RLi or RMgX provide the alkyl derivatives [R = Me (3), Et (4), {sup n}Pr (5), {sup n}Bu (6), and CH{sub 2}SiMe{sub 3} (7)]. Kinetic and mechanistic studies of the 3 {yields} 8 rearrangement reveal that methyl migration is strictly intramolecular. The reactions of this model system delineate one process by which heterocyclic C-N bonds are cleaved and offer new insight as to how nitrogen heterocycles may be further degraded after C-N bond cleavage in hydrodenitrogenation catalysis. 74 refs., 7 figs., 5 tabs.

A family of novel linear 1,10-phenanthroline-based (A-D-A-D-A) and oligothiophene-based (A-D-D-D-(D)-A) heterocyclic aromatic fluorescence compounds having N-containing imidazole and pyridine tails with effective π-conjugated systems, prepared by the combination of carbon-carbon (C-C) bond and carbon-nitrogen (C-N) bond cross-coupling reactions, is described. They have molecular lengths of more than 2.30 nm in the cases of 4, 6, 9, and 26, various D-A spacers, and certain N-coordination sites (phen, imidazole, and pyridine). X-ray single-crystal structures of 13 compounds reveal a variety of trans and cis configurations with different dihedral angles between adjacent aromatic heterocycles. Synthetic, computational, and spectral studies have been made to reveal the differences between cross-coupling approaches on the C-C bond and C-N bond formation as well as band gaps and energy levels and optical and electrochemical properties for related compounds. The influences of introducing a β-methyl group to the thiophene ring on reaction activity, solubility, and conformation of related compounds have also been discussed.

The salen complexes ML (M II =Cu, Ni, Co) and the corresponding tetrahydrosalen complexes M[H 4 ]L (M II =Cu, Ni) were prepared and characterized by their vis absorption and EPR spectra, by their magnetic moments, and by cyclic voltammetry in acetonitrile

Treatment of tertiary amines with diazoacetate in the presence of a catalytic amount of an iron salt, FeCl(3), in ethanol gave glycine derivatives. In this reaction, a carbon-nitrogen single bond of the amine was cleaved.

A facile synthesis of sulfonylamidinesvia carbon–nitrogen bond formation mediated by FeCl3 was developed and an interesting major product of cyclic tertiary amine was observed, which showed the good selectivity of FeCl3-mediated activation of cyclic α-C–H bonds of cyclic tertiary amines.

Triethyl phosphite deoxygenation of 2-(2-nitrophenyl)imidazo[1,2-a][1,8]naphthyridine (3) led to the C-insertion to give the indoloimidazonaphthyridine 5. Our attempt to promote the N-insertion by blocking the C-3 position failed. Triethyl phosphite deoxygenation of 1-nitroso-2-(4-fluorophenyl)imidazo[1,2-a][1,8]-naphthyridine (12) led to the corresponding amine structure (15). Thermolysis and photolysis of 6,8-dimethyl-2-(2-azidophenyl)imidazo[1,2-a][1,8]naphthyridine (17) are also reported.

The pathways corresponding to the most energetically favorable decomposition reactions that can be envisaged for o-nitrotoluene (and 20 of its derivatives) have been studied, using density functional theory, in order to evaluate the influence of substituents' nature (nitro, methyl, amino, carboxylic acid, and hydroxyl) and position. The first mechanism consists of the direct dissociation (homolysis) of the carbon nitrogen bond (CH(3)C(6)H(4)NO(2) = CH(3)C(6)H(4) + NO(2)) whereas the second one is a more complex process initiated by C-H alpha attack and leading to the formation of anthranil and water (C(6)H(4)C(H)ON + H(2)O). For each compound, the initial step of this last channel is the rate limiting one, the Gibbs activation energy of all systems being very close, that is all in the 40-44 kcal/mol range. More important variations have been observed for the C-NO(2) homolysis Gibbs activation energies (46-60 kcal/mol). These variations have been related to electron donor-acceptor properties of substituents by considering significant correlations (R(2)0.9) with the Hammett parameters (sigma). Nevertheless, though the influence of substituents on the direct breaking of the C-NO(2) bond was important, the C-H alpha attack remained finally the major decomposition channel for the studied compounds. Our study underlines the complexity of the decomposition process in nitroaromatic compounds and casts some doubts on the characterization of the energetic properties of such molecules only on the basis of C-NO(2) homolysis.

Nitrogen heterocycles bearing a nonbasic nitrogen atom and other defined structural features as exemplified by 9,10-dimethoxy-3,4,6,7-tetrahydro-2H-pyrimido [6,1-a] isoquinoline-2,4-dione (1), 8-oxypseudopalmatine (22), 8-oxypseudoberberine (25), rutaecarpine (39), and related systems, on heating with excess sodium hydride in polar aprotic solvents, undergo a facile carbon-nitrogen bond cleavage reaction to give new nitrogen heterocycles with an arylvinyl group as one of the substituents

The RuH2(CO)(PPh3)3-catalyzed reaction of 2-amino-6-methylacetophenone with phenylboronic acid 2,2-dimethyl-1,3-propanediol ester in refluxing toluene gave the corresponding phenylation product in 83% yield via aryl carbon−nitrogen bond cleavage. This reaction involves two notable features: (1) the coupling proceeds via the oxidative addition of an aryl carbon−nitrogen bond in anilines to the ruthenium complex, and (2) C−C bond formation takes place via transmetalation between the Ru−NR2 species and organoboronates.

Easily accessible benzamide-derived hemilabile phosphine ligands were efficiently prepared through ortho-directed lithiation of the corresponding N,N-diethylbenzamide followed by quenching with chlorodialkylphosphines. These structurally simple hemilabile ligands were found to be highly effective in palladium-catalyzed amination of aryl and heteroaryl chlorides. Various sterically congested and functionalized aryl halide substrates were compatible in these reaction conditions. By using optimized reaction conditions, remarkable catalyst productivity (total turnover number up to 8400) was obtained.

We present here carbon-nitrogen bond formation via a coupling reaction of 2-iodo-selenophene catalyzed by Cu(I) in the presence of a base and an inexpensive ligand, and establish the first route to obtaining 2-nitrogen-selenophene derivatives in good yields. We can anticipate that this reaction works well with oxazolidinones, lactams, and aliphatic and aromatic amides, as nitrogen sources, in the absence of any supplementary additives. In addition, the reaction proceeded cleanly under mild reaction conditions and was sensitive to the ratio of amide/2-iodo-selenophene, as well as the nature of the ligand, base, and solvent.

Thorium(IV) alkyl and aryl complexes of the type (C(5)Me(5))(2)ThR(2)(R = CH(2)Ph, Ph) have been found to mediate the facile ring-opening and dearomatization of the pyridine ring of pyridine N-oxide under ambient conditions to afford the first thorium eta(2)-(O,N)-oximate complexes.

Reaction of ArNCO with syn-[MoO(mu-O)(S2CNR2)]2 or syn-[MoO(mu-NAr)(S2CNR2)]2 at 110 degrees C leads to the facile formation of bridging ureato complexes [Mo2(NAr)2(mu-NAr){mu-ArNC(O)NAr}(S2CNR2)2](Ar = Ph, p-tol; R = Me, Et, Pr), formed upon substitution of all oxo ligands and addition of a further equivalent of isocyanate across one of the bridging imido ligands. Related sulfido-bridged complexes [Mo2(NAr)2(mu-S){mu-ArNC(O)NAr}(S2CNR2)2] have been prepared from syn-[Mo2O2(mu-O)(mu-S)(S2CNR2)2]. When reactions with syn-[MoO(mu-NAr)(S2CNEt2)]2 were followed by NMR, intermediates were observed, being formulated as [Mo2O(NAr)(mu-NAr){mu-ArNC(O)NAr}(S2CNEt2)2], which at higher temperatures convert to the fully substituted products. A crystallographic study of [Mo2(N-p-tol)2(mu-S){mu-p-tolNC(O)N-p-tol}(S2CNPr2)2] reveals that the bridging ureato ligand is bound asymmetrically to the dimolybdenum centre-molybdenum-nitrogen bonds trans to the terminal imido ligands being significantly elongated with respect to those cis-a result of the trans-influence of the terminal imido ligands. This trans-influence also leads to a trans-effect, whereby the exchange of aryl isocyanates can occur in a regioselective manner. This is followed by NMR studies and confirmed by a crystallographic study of [Mo2(N-p-tol)2(mu-N-p-tol){mu-p-tolNC(O)NPh}(S2CNEt2)2]--the PhNCO occupying the site trans to the terminal imido ligands. Ureato complexes also react with PhNCS, initially forming [Mo2(NAr)2(mu-S){mu-ArNC(O)NAr}(S2CNR2)2], resulting from exchange of the bridging imido ligand for sulfur, together with small amounts of [Mo2(NAr)2(mu-S)(mu-S2)(S2CNEt2)2], containing bridging sulfide and disulfide ligands. The ureato complexes [Mo2(NAr)2(mu-S){mu-ArNC(O)NAr}(S2CNR2)2] react further with PhNCS to give [Mo2(NAr)2(mu-S)2(S2CNR2)2]n (n = 1, 2), which exist in a dimer-tetramer equilibrium. In order to confirm these results crystallographic studies have been carried out on [Mo2(N-p-tol)2(mu-S)(mu-S2)(S2CNEt2)2] and [Mo2(N-p-tol)2(mu-S)2(S2CNPr2)2]2.

The reactivity of a series of amines with various structures and different numbers of hydrogen atoms on the carbon atoms in the α and β position was used to evidence the C–N bond scission mechanism in the presence of H2S on Pt based catalysts (deposited on alumina, zirconia and silica–alumina) and compare it with the mechanism on a NiMoP on alumina sulfide catalyst. The effect of the H2S partial pressure was also checked. Catalytic activities (amine overall conversion, C5 hydrocarbon formation, and amine disproportionation) deeply depend on the structure of the N-containing molecule. Tert-pentylamine is the most reactive molecule for sulfide catalysts whereas, in the case of n-pentylamine, Pt on zirconia was found to be the most efficient for C–N bond breaking. Such properties cannot be related to the acidic properties of the support but to a unique support–metal interaction, since alumina or silica–alumina supported platinum catalysts do not present this behaviour.

Catalytic amounts of ytterbium triflate were used to promote the cleavage of aromatic imines with acylation reagents, including acyl chlorides and anhydrides or sulfonyl chlorides, to obtain aldehydes and acyl amides or sulfonamides in high yields. Products of Friedel–Crafts acylation have not been detected.

The dinuclear dinitrogen complex ([P2N2]Zr)2(mu-eta2:eta2-N2) reacts with terminal aryl alkynes to generate a new species in which the dinitrogen unit has been functionalized. The products formed have the general formula ([P2N2]Zr)2(mu-eta2:eta2-N2CCAr)(mu-CCAr) and display a styryl-hydrazido unit bridging the two Zr centers along with a bridging arylalkynide. The crystal structures of three of these products are reported. A mechanism is proposed for this process that involves cycloaddition of the alkyne to the side-on dinitrogen unit followed by protonation of the Zr-C bond by a second equivalent of terminal alkyne. A fluxional process is operative in solution that equilibrates the phosphorus nuclei at high temperature; in the slow exchange limit, the two [P2N2]Zr ends of complex are inequivalent as evidenced by four resonances in the 31P NMR spectrum for the inequivalent phosphorus donors. This C-N bond-forming reaction is unique in that an activated dinitrogen fragment undergoes a reaction with an alkyne.

Alkyl and aryl phosphites and phosphines react with compounds having weak heteroatom–heteroatom bonds, such as SS, OO, etc., and with azo compounds to form reactive phosphonium salts. These phosphonium salts in turn promote “redox” condensation reactions with compounds having active hydrogens. The condensation reaction of alcohols using the redox couple of a triaryl- or trialkylphosphine and a dialkyl azodicarboxylate has become known as the Mitsunobu reaction, based on his pioneering work in the late 1960s. The overall reaction is summarized, wherein the alcohol (R1OH) and acidic compound (H–Nu) are condensed to form product (R1–Nu), while triphenylphosphine is oxidized to triphenylphosphine oxide and the azodicarboxylate is reduced to the hydrazine. Although the typical redox combination is diethyl azodicarboxylate (DEAD) and triphenylphosphine, many other combinations have found selected use. The reaction is generally limited to primary and secondary alcohols, although tertiary alcohols react in a few intramolecular and intermolecular reactions. For secondary alcohols the reaction usually proceeds with clean inversion of stereochemistry. The acidic component of the reaction generally has an aqueous pKa

A facile synthesis of sulfonyl amidines via carbon-nitrogen bond formation mediated by FeCl(3) was developed and an interesting major product of cyclic tertiary amine was observed, which showed the good selectivity of FeCl(3)-mediated activation of cyclic alpha-C-H bonds of cyclic tertiary amines.

In CD3CN solutions the kinetic parameters characterising rotation about the CNMe2 and CNH2 bonds in [UO2(1,1-DMU)5]2+ (1,1-DMU = 1,1- dimethylurea) were determined as: k(265 K) = 39.1 ± 0.4 and 2960 ± 60 s−1, ΔH‡ = 49.1 ± 0.76 and 61.1 ±0.5 kJ mol−1, ΔS† = −28.3 ± 2.7 and 53.1 ± 2.2 J K−1 mol−1 respectively from 1H NMR studies. Resonances arising from the three isomeric 1,3-DMU (= 1,3-dimethylurea) ligands were observed for [UO2(1,3-DMU)5]2+ in CD3CN solution and the kinetic parameters characterising their isomerisations were also determined. The three isomers of 1,3-DMU have not previously been detected in solution and it appears that coordination of 1,3-DMU to UO22+ increases the barrier to rotation about the carbon nitrogen bond, as is also shown to be the case for 1,1-DMU.

The dihydride [Os3H2(CO)10] reacts with the diazoalkane ButCHN2 to give [Os3H(ButCHNNH)(CO)10] in the same way as reported for other diazoalkanes. A compound believed to be [Os3(µ-CH2But)(µ-ButCHNNH)(CO)10] is also formed. However, [Os3H2(CO)9(PMe2Ph)] reacts with ButCHN2 to give a good yield of a novel type of compound [Os3H2(ButCHNNCO)(CO)8(PMe2Ph)](X-ray structure reported). Instead of ButCHN2 addition being followed by insertion into an Os–H bond, the ButCHN2 molecule couples with CO to give the µ3-isocyanate ligand RNCO (R = ButCHN) bonded to the Os3 triangle through N and C atoms. Protonation with CF3CO2H leads by C–N cleavage to [Os3H2(ButCHNNH)(CO)9(PMe2Ph)]+. On deprotonation of this cation, the C–N bond reforms to regenerate the ButCHNNCO compound, but the isomer [Os3H(ButCHNNH)(CO)9(PMe2Ph)] is also formed. This monohydride isomerises thermally to an isomer with the same formulation that is also formed by thermal substitution of [Os3H(ButCHNNH)(CO)10]. In all, three isomers have been identified, two differing in the positions of PMe2Ph substitution which are clearly established by JPH values for the hydrido-ligands.

The temperature-dependent pmr spectrum of Rh(MePhdtc)3 was examined in CDCl3 solvent over the temperature range −34° to +51°. The complex is stereochemically non-rigid and isomerizes by a C-N bond rotation mechanism. A line shape analysis yielded a value of δG#=61.5 ± 4.2 kJ mol−1. This barrier to rotation is large relative to similar complexes of Fe(II) and Fe(III) but similar to values for Fe(IV) and Co(III). Metal-centered optical inversion is slow over the temperature range studied.

Die Thermolyse eines Gemisches aus a,a-Diphenyl-N-benzhydrylnitron und seines [p,p′,p",p"′-D4 ]Derivates, dessen Darstellung beschrieben wird, wird untersucht.

Treatment of N-(p-nitrobenzyl)pyridinium benzenesulphonate with aqueous sodium hydroxide gives pp′-di-formylazoxybenzene (40%), C-(p-nitrophenyl)-N-benzaldehyde nitrone (30%) and p-nitrobenzaldehyde (7·5%). N-(1-p-Nitrophenylethyl)pyridinium benzenesulphonate and N-(p-nitrodiphenylmethyl)pyridinium benzenesulphonate react with aqueous sodium hydroxide to give pp′-diacetylazoxybenzene (75%) and p-nitrobenzophenone (40%) respectively. The nature of the substituents on the benzylic carbon affects the nature of the products.

Dodecacarbonyltriruthenium reacts in refluxing cyclohexane with 1-dimethylaminobut-2-yne (MeC CCH2NMe2) to give good yields of the isomers [Ru3H(CO)9(µ3-MeCCCHNMe2)](1) and [Ru3H(CO)9-(µ3-MeCCHCNMe2)](2) which are related in stoicheiometry (although perhaps not in structure) to known complexes containing µ3-allenyl (R1CCCHR2) or diosmium-substituted µ3-allyl (R1CCHCR2) ligands. The osmium analogue of complex (1) is obtained similarly from [Os3(CO)12] but [Os3(CO)10-(MeCN)2] reacts at room temperature with the alkyne giving [Os3H(CO)9(µ3-MeCCCH2)] by C–N bond cleavage. Rotation about the C–N bond in complex (1) in chloroform solution is restricted but the rate is accelerated by the addition of small amounts of CF3CO2H while, in neat CF3CO2H, compound (1) is protonated to give [Ru3H2(CO)9(MeCCCHNMe2)]+ for which the rotation barrier is much higher. Neutralisation of acidic solutions of complex (1) gives up to 15% of the but-2-ynal compound [Ru3H2(CO)9(µ3-MeC2CHO)] by hydrolysis. Compound (1) is converted totally into (2) in refluxing hexane but in the presence of H2 hydrogenolysis of the C–N bond also occurs to give the compounds [Ru3H2(CO)9(µ3-MeC2Me)], [Ru3H(CO)9(µ3-MeCCCH2)] and [Ru3H(CO)9(µ3-MeCCHCH)].