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In many reactions involving selenosulfonate or thiosulfonate, the sulfone group often leaves in form of benzenesulfinic acid or sodium benzenesulfinate. A one-pot two-step reaction of selenosulfonate with isocyanides and allyl alcohol under aqueous conditions to afford selenocarbamates and allyl sulfone compounds is reported. The sulfinic acid as the first-step side product is converted to the allyl sulfone compound by water promoted reaction with allyl alcohol. Water acts as both an oxygen source of selenocarbamates and as a promoter to drive the second step reaction. The reactions have the advantages of mild conditions, green, environment-friendly, and high atomic economy.

A study on the reactivity of NHC cobalt half-sandwich complexes [(η5-C5R15)Co(R22Im)(η2-C2H4)] (R1 = H; R2 = Me 1, iPr 2) and [(η5-C5R15)Co(R22Im)(η2-C2H3{SiMe3})] (R1 = H, R2 = Me 3, iPr 4; R1 = Me, R2 = Me 5, iPr 6) towards selected perfluoroarenes is presented (R2Im = 1,3-di(organyl)-imidazolin-2-ylidene). The reaction with hexafluorobenzene, perfluorotoluene and decafluorobiphenyl at 100 °C led to the isolation of the cobalt(II) complexes [CpCo(iPr2Im)(C6F5)] 7, [CpCo(iPr2Im)(C7F7)] 8, [CpCo(iPr2Im)(C12F9)] 9, [Cp*Co(iPr2Im)(C6F5)] 10, [Cp*Co(iPr2Im)(C7F7)] 11 and [Cp*Co(iPr2Im)(C12F9)] 12 (Cp* = η5-C5{CH3}5), Cp = η5-C5H5). The cobalt(II) fluoride [CpCo(iPr2Im)(F)] was detected as a side product of these reactions. The reaction of [CpCo(R22Im)(η2-C2H4)] (R2 = Me 1, iPr 2) with C6F6 and C7F8 at 60 °C afforded the dinuclear complexes [{CpCo(R22Im)}2(μ-η2,η2-C6F6)] (R2 = Me 13, iPr 14) and [{CpCo(R22Im)}2(μ-η2,η2-C7F8)] (R2 = Me 15, iPr 16). Furthermore, the dinuclear complexes [{CpCo(Me2Im)}2(μ-η2,η2-C10F8)] 17, [{CpCo(iPr2Im)}2(μ-η2,η2-C10F8)] 18 and mononuclear [CpCo(iPr2Im)(η2-C10F8)] 19 were isolated from the reaction of 1 and 2 with octafluoronaphthalene at room temperature. Based on the experimental data a mechanism is proposed for the C–F bond activation of perfluoroarenes with complexes [Cp(*)Co(NHC)(olefin)]. Transfer of [Cp(*)Co(NHC)] to the perfluoroarene, which is limited by the activation barrier to replace the alkene ligand, affords mononuclear cobalt complexes [Cp(*)Co(NHC)(η2-ArF)]. Ligand dismutation at higher temperatures leads to dinuclear complexes [{Cp(*)Co(NHC)}2(μ-η2,η2-ArF)], which are precursors for the formation of the cobalt(II) complexes [Cp(*)Co(NHC)(ArF)] and [Cp(*)Co(NHC)(F)]. One electron oxidative addition prevails in the C–F bond activation step using these cobalt half-sandwich complexes.

Attempts to prepare hexafluoroacetylacetonate (hfac) piano stool complexes of pentamethylcyclopentadienyl Cp∗ iridium and rhodium led to a surprising array of unexpected products. The desired complex, Cp∗M(hfac)Cl, was obtained following the reaction of sodium hexafluoroacetylacetonate (hfacNa) with [Cp ∗MCl 2 ] 2 in dichloromethane. Variations of this synthetic method resulted in twelve unique crystal- lographically identified products, eleven of which contain the hfac ligand or a trifluoroacetylacetonate (TFA) ligand, either coordinated to the metal or as a non-coordinating anion. Five dinuclear Cp ∗iridium hydroxo-bridged products with various fluorinated non-coordinating anions were obtained. The most in- triguing two complexes are trinuclear Cp ∗Ir III hydroxo-bridged clusters that have, at their core, an Ir 3 NaO 4 cubane structure. Attempts to devise rational syntheses of the hydroxo-bridged cluster compounds were not successful. Generation of the TFA moieties likely occurred following degradation of Cp ∗Ir(hfac)Cl. The reaction between [Cp ∗MCl 2 ] 2 and 1,1,1-trifluoroacetylacetonate (tfac) proceeded as expected to give Cp ∗M(tfac)Cl with no observed side product formation, indicating that the metal-coordinated tfac moiety is significantly more stable than the metal-coordinated hfac moiety. Published (Publication status)

We demonstrate that Ir-catalyzed C-C bond activation in biphenylenes followed by a reaction with tribenzocyclyne is a suitable method for synthesizing strained and unknown monoadducts with the tetradehydrotetrabenzo[a,c,e,i]cyclododecene scaffold ([12]annulenes). Modification of reaction conditions also furnished [12]annulene products with cis and/or trans double bonds formed by hydrogen transfer. The [9]annulene side product was formed upon the reaction of the benzyl radical with tribenzocyclyne during the Bergman cyclization. All isolated compounds were fully characterized by HRMS, NMR, and X-ray diffraction analysis.

A zirconium/nickel-mediated one-pot synthesis of ketones is reported. In the presence of Zn or Mn, Cp2 ZrCl2 was found to dramatically accelerate the coupling and suppress side product formation via an I→SPy displacement at the same time. Unlike Zn/Pd- and Fe/Cu-mediated one-pot ketone syntheses, the new method is effective for nucleophiles bearing OR or equivalent functional groups at the α-position. A mechanism comprising a nickel catalytic cycle, a zirconium catalytic cycle, and Zr→Ni transmetalation is proposed, and Cp2 ZrCl2 and/or low-valent Zr species are suggested to play crucial dual roles.

Dihydropyrimidine derivatives possess great potential to be used as a precursor for the synthesis of wide diverse dihydropyrimidine-like derivatives. In this research, the title compounds were synthesized through the reaction between 5-acetyl-4-(2,5-dimethoxyphenyl)-6-methyl-3,4-dihydropyrimidin-2(1H)-thione and 2,5-dimethoxybenzladehyde under aldol condensation condition. The title compound, (E)-3-(2,5-dimethoxyphenyl)-1-{[(4-(2,5-dimethoxyphenyl)-6-((E)-2,5-dimethoxystyryl)-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl)]}prop-2-en-1-one (yield 15%), was obtained as major product, whereas (E)-3-(2,5-dimethoxyphenyl)-1-{[(4-(2,5-dimethoxyphenyl)-6-methyl-2-thioxo-1,2,3,4-tetrahydro pyrimidin-5-yl)]}prop-2-en-1-one (yield 8%) as side product through vinylogous aldol condensation.

The LDA-induced coupling of 2′,3′,5′-O-protected uridine with diethyl chlorophosphate, during the synthesis of 6-phosphonouridine, is accompanied by the formation of an unexpected side product. LDA adds slowly to the C4 position of the 2′,3′,5′-O-protected uridine after the initial reaction with diethyl chlorophosphate. The presence of the phosphorochloridate facilitates the side reaction. This observation accounts for the previously reported low yield when conducting the coupling reaction for longer durations and suggests a new route for the synthesis of N-alkylated 6-phosphonocytidine analogues.

A Ru(II)-catalyzed, redox-free, two-fold aromatic/allylic C–H bond activation of aromatic acids with allylic acetates to give (Z)-3-ylidenephthalides is described. In the reaction, H2 was formed as a side product. The detailed mechanistic investigation and DFT studies including the transition-state analysis support the postulate that the C–H allylation takes place at the ortho position of aromatic acids with allylic acetates followed by intramolecular cyclization at the allylic C(sp3)–H via a π-allylruthenium intermediate.

During the preparation of 1-tributylstannyl glucals from 1-phenylsulfinyl glycosides an unexpected side reaction was observed for 2,3,4,6-tetra-O-methoxyethoxy (MEM) protected 1-phenylsulfinyl glucoside. Treatment of the latter with lithium diisopropylamide (LDA) afforded the expected, fully MEM protected 1-phenylsulfinyl glucal accompanied by variable amounts of an unexpected 1-phenylsulfinyl 2-hydroxymethyl-3,4,6-tri-O-methoxyethoxyglucal. The amount of the side product rose with increasing concentration of the starting material.

Methyl adamantane-1-carboxylate and methyl (1-adamantyl)acetate react with acetonitrile in the presence of sodium hydride to give 3-(1-adamantyl)-3-oxopropanenitrile and 4-(1-adamantyl)-3-oxobutanenitrile, respectively. Reaction involving methyl (1-adamantyl)-acetate produces also 2-(1-adamantyl)-N-(E-1-cyanoprop-1-ene-2-yl)acetamide; the structure of this side product was established by X-ray diffraction analysis.

Glycosylation of 3α-acetoxy-12β,25-dihydroxy-20S,24R-epoxydammarane (2) by 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosylbromide (5) in the presence of Hg(CN)2 in nitromethane at 22°C produced the acetylated 12,25-di-O-β-D-glucopyranoside of 3α,12β,25-trihydroxy-20S,24R-epoxydammarane (6) and also formed the side product 3α-acetoxy-12β-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyloxy)-24-cyano-20S,24S-epoxydammarane (8). Condensation of 3α,12β-diacetoxy-25-hydroxy-20S,24R-epoxydammarane (3) with glycosyl donor (5) under the same conditions gave the hexaacetate of the 25-O-β-D-glucopyranoside of 3α,12β,25-trihydroxy-20S,24R-epoxydammarane and also formed a mixture of C-24-epimers (1:1) of 3α,12β-diacetoxy-24-cyano-20S,24ξ-epoxydammarane (10a,b).

C-, N-, and/or O-methylation products were generated from 11H-isoindolo[2,1-a]quinazoline-5-one upon treatment with NaH followed by iodomethane under air, and possible recrystallization from methanol. Two products were fully characterized by NMR and X-ray diffraction analysis. In accordance with the HSAB principle, this soft methylating agent (MeI) leads mainly to the C,C-dimethylated product 11,11-dimethyl-11H-isoindolo[2,1-a]quinazoline-5-one, which was previously not observed, beside the N-methylated product, in a procedure using methyl tosylate as a hard methylating agent of the same substrate in the initial absence of a base. A mechanism is finally proposed for the formation of methyl 2-(3-methyl-4-oxo-3,4-dihydroquinazolin-2-yl)benzoate as an oxidation side product.

The readily synthesized trichloro acetimidamide was found to be an excellent directing group for the directed C–H-allylation reactions. Depending on the allylating agent used, selectively either mono- or diallylated products were readily synthesized. Moreover, the trichloro acetimidamide directing group was found to be highly efficient even at lower temperature for the C–H-allylation reaction. Due to mildness of the reaction conditions, double bond isomerization or cyclization to indole side product was not observed.

A series of N -( p -X-phenyl)- N ′-( p -toluenesulfonyl)1,2-ethylenediamines compounds, TsN(H)CH 2 CH 2 N(H)PhX, were synthesized by the uncatalyzed ring opening reaction of N -tosylaziridine with p -X-aniline derivatives in pure water at 50 °C. No solvolysis product was observed and the only side product was that of a subsequent ring opening reactions of N -tosylaziridine with the product anilines leading to substituted diethylenetriamines, XPhN(CH 2 CH 2 NTs) 2 .

The reaction of chlorodeoxypseudoephedrine or chlorodeoxynorpseudoephedrine hydrochlorides with sodium dithiocarbonate in stirring ethanol at 0 °C to stereoselectively afford the corresponding cis -thiazolidinethiones in good yields (81% and 95%) is reported. The in situ formation of a cis -aziridine to explain the presence of trans -thiazolidinethione as a side product is proposed when the same reaction was carried out at room temperature. In addition, a 70:30 mixture of trans -isomers of a thiazolidinethione/isothiazolidinethione was formed when a cis -aziridine NH was reacted with carbon disulfide in refluxing ethanol. The analogous reaction with cis -aziridine N–Me stereoselectively affords the corresponding cis -thiazolidinethione. The 1 H and 13 C NMR data of the thiazolidinethiones were assigned. cis -3,4-Dimethyl-5-phenylthiazolidine-2-thione was crystallized from ethanol and its X-ray diffraction structure was analyzed.

On the basis of Templeton's experiment (West, N. M. ;et al. Organometallics 2008, 27, 5252), the mechanisms of the main and the side reactions between (Cl-nacnac)Pt(H) (Cl-nacnac: bis(N-aryl)-β-diiminate) and a terminal alkyne were investigated by density functional theory. Our study shows that the 1, 2-insertion of t-BuC≡CH into the Pt―H bond generates the main products and that C-C bond formation is the rate-determining step. The 2, 1-insertion of t-BuC≡CH into the Pt-H bond generates the byproducts and alkyne insertion is the rate-determining step. Based on the mechanisms of the main and side reactions the presence of the main product and the by-product could be explained. We found that the main product is thermodynamically controlled while the side product is kinetically controlled.

Reaction of [Rh(CO)2](μ-Cl)]2 with bis-1,2-(di{4-dimethylaminophenyl)phosphino-ethane (L) gives the monomeric Rh(I) complex of type cis-[RhCl(L)(CO)] that was separated from a side product of type [Rh(L)2]Cl, and characterised by X-ray crystallography. This complex reacts with methyl iodide at high temperature to give the Rh(III) acetyl complex, [Rh(I)2(C(O)Me)(L)], which was also structurally characterised by X-ray crystallography. There is no sign of quaternisation of the dimethylamino groups under these conditions. This complex is soluble in organic solvent and insoluble in the polar media used in methanol carbonylation (AcOH/H2O/MeOH). However, in the presence of HI, this complex is readily soluble in AcOH/H2O/MeOH, in contrast to [Rh(I)2(C(O)Me)(dppe)] and most other Rh-acetyl complexes of diphosphine ligands.

A method has been developed for the synthesis of 4-(2-quinolinyl)-1,2,3,3a - tetrahydropyrrolo-[1,2-a]quinolines based on the 1,3-dipolar cycloaddition reaction of α,β-unsaturated carbonyl compounds to 2,3'-biquinolinium salts. Oxidation in benzene using Mn0 2 gave 4-(2-quinolinyl)-pyrrolo[1,2-a]quinolines. It was found that a side product of the 1,3-dipolar cycloaddition is 7,14-dibenzoyl-6,13-di(2-quinolyl)-6a,7,13a,14-tetrahydro-7a,14a-diazadibenzo[a,h]anthracene.Reaction of 1'-phenacyl-2,3'-biquinolinium salts with hydroxylamine in acetic acid gave 4-(2-quinolyl)imidazo-[1,2-a]quinolines.

The synthesis is reported of 2-hydroxy-1,2,2-triphenylethanone esters of carboxylic acids by the reaction between 2-chloro-1,2,2-triphenylethanone and a carboxylic acid in the presence of silver carbonate and silver tetrafluoroborate. Photolysis of the esters occurs rapidly on irradiation with a medium-pressure mercury lamp through quartz or Pyrex to return the carboxylic acid. The side product of the photolysis is benzo[b]phenanthro[9,10-d]furan, formed through a tandem process involving initial generation of 2,3-diphenylbenzofuran, photochemical cyclisation and re-aromatisation by aerial oxidation.

Efficient, scalable cobalt-catalyzed redox-neutral [4+2] annulation of readily available oximes and alkyne is reported. The developed synthetic methodology is widely applicable and tolerates various functional groups including heterocycles. A stable Cp*Co(III) neutral complex is employed as the catalyst for this redox-neutral [4+2] annulation reaction, which progresses smoothly by way of a reversible cyclometallation without any external oxidizing agent, and produces only water as the side product.

Simple Bronsted acids such as p-toluenesulfonic acid monohydrate (PTS) or polymer-bound p-toluenesulfonic acid efficiently catalyze the direct nucleophilic substitution of the hydroxy group of allylic and benzylic alcohols with a large variety of carbon- and heteroatom-centered nucleophiles. Reaction conditions are mild, the process is conducted under an atmosphere of air without the need for dried solvents, and water is the only side product of the reaction.

Oligophosphanide Anions: Syntheses and Molecular Structures of [K2(PMDETA)2(P4Ph4)], [K2(PMDETA)(P4tBu4)]2 and [K(PMDETA)(THF){cyclo-(P5tBu4)}] (PMDETA = NMe(CH2CH2NMe2)2) The alkali metal tetraphosphanediides [K2(PMDETA)2(P4Ph4)] (1) and [K2(PMDETA)(P4tBu4)]2 (2) [PMDETA = NMe(CH2CH2NMe2)2] were synthesized via reaction of PhPCl2 or tBuPCl2 with 2.5 equiv. potassium and characterized by X-ray crystallography and 31P NMR spectroscopy. As in other ion contact complexes of the type M2(P4R4) (M = alkali metal) the solid-state structures are retained in solution. While 1 could be prepared in comparatively good yield (54 %), 2 was only isolated in very modest yield and with low purity as [K(PMDETA)(THF){cyclo-(P5tBu4)}] (3) was formed as a side product in this case. 3 was also characterized by X-ray crystallography and 31P NMR spectroscopy.

Palladium-catalyzed carbonylative cross-coupling reaction of ethynylstibane (PhSbPh(2)) and aryl iodides (Ar-I) is described. The reaction of the stibanes and the halides under 1 atm of carbon monoxide in N,N-dimethylacetamide using a combination of 5 mol% Pd(OAc)(2) and 4 equivalents (20 mol%) of PPh(3) brought about carbonylative cross-coupling reaction to afford arylethynylketones [ArC(O)Ph] in good yields along with a small amount of directly coupled products, aryl acetylens (ArPh). Formation of the side product was completely suppressed by conducting the reaction under high CO pressure (20 atm) conditions. The present method provides a variety of carbonylated products in good yield even with electron-deficient aryl iodides which usually give inferior results due to their tendency to undergo decarbonylation in the cross-coupling reaction of ethynylstibanes and acyl halides.

Two efficient routes to 1-tert-butyl-4-chloropiperidine are described. In the first route, the key thionyl chloride mediated chlorination reaction features the use of tetrabutylammonium chloride as an additive that effectively suppresses the formation of an elimination-derived side product. In the second route, a novel alternative synthesis of 1-tert-butyl-4-chloropiperidine was developed in which the tertiary butyl group on the nitrogen is efficiently generated through the addition of methylmagnesium chloride to a dimethyliminium salt in 71% overall yield.

The title compound, isobutyltin(IV) dichloride hydroxide N,N-dimethylformamide solvate {(iBuSnCl 2 (OH) (DMF)) 2 }, an accidental side product from the reaction of isobutyltin(IV) trichloride with moisture in N,N-dimethyl- formamide, exhibits structural features similar to those of the corresponding hydrates of monoorganotin(IV) dihal- ide hydroxides characterized by a central four-membered rhombic Sn-O ring and tin atoms with a distorted octahe- dral coordination.

The formation of the monoaryloxylation products is mostly accompanied by the formation of significant amounts of separable, but non-isolated, biaryloxylation products, whereas biaryloxylation proceeds in most cases regioselectively without formation of a monoaryloxylation side product.

The reaction between Cp(PPh 3 ) 2 Ru–CN and CuCl 2 results in Cp(PPh 3 ) 2 Ru–CN–CuCl ( 1 ) as the main product and Cl(CH 3 CN)(PPh 3 )Ru{CN–CuCl}{NC–Ru(PPh 3 ) 2 Cp} 2 ( 2 ) as the side product. cis -(bpy) 2 Fe(CN) 2 reacts with both CuCl 2 and CuCl to form [(bpy) 2 Fe(CN)(CN–CuCl 2 )] x ( 3 ) and [(bpy) 2 Fe(CN)(CN–CuCl)] x ( 4 ). Upon attempts at recrystallization the former partly decomposes with formation of (bpy) 2 Fe{CN–CuCl 2 (bpy)} 2 ( 5 ). Electrochemical data of the complexes are reported. Complexes 1 , 2 , and 5 were identified by structure determinations.

The first synthesis of the methylene-bridged binary carbazole alkaloids bismurrayafoline-A and chrestifoline-A is described. As an interesting side product, a likewise benzylically connected trimer was identified, a potential natural product.

A new, improved synthesis of [Pd{CN(tBu)(CH)2N(tBu)}2] (1) and its use as a catalyst in coupling reactions, including aminations, is presented. An interesting side product formed in the synthesis of 1, [Pd(?3-C4H7){(CN(tBu)(CH) 2N(tBu)}Cl] (2), is also discussed. © 2001 Elsevier Science B.V.

CHF 2 OCH 3 (HFE-152a), an important starting material for synthesizing various C 2 hydrofluoroethers and a prospective alternative to CH 3 CF 2 Cl (HCFC-142b), has been found to be effectively produced from the reaction of CHF 2 Cl (HCFC-22) with alkali metal carbonates in methanol. Some alkali metal carbonates induce selective production of CHF 2 OCH 3 with a small amount of CH(OCH 3 ) 3 , a major side product. Activities of alkali metal carbonates for producing CHF 2 OCH 3 are in the order of K 2 CO 3 >Na 2 CO 3 >Li 2 CO 3 , suggesting that the solubility and ionization tendency of alkali metal carbonate in methanol play important roles in the reaction.

When a large excess of dimethyl 3,3-dimethylcyclopropene-1,2-dicarboxylate was used in a reaction with Pd2(dba)3·CHCl3, only reduced yields of tetramethyl 3,3,7,7-tetramethyl-5-pallada-trans-tricyclo[4.1.0.02,4]heptane-1,2,4,6-tetracarboxylate were obtained. One side product was the new palladacyle dimethyl 3-(3,4-bis(methoxycarbonyl)-5,5-dimethyl-5H-furan-2-ylidene)-1,1,4,4-tetramethyl-6-oxodihydro-5-oxa-2-palladacyclopropa[c]pentalene 1a,3a-dicarboxylate; its structure was proven by a crystal structure analysis of the bpy complex. The other side products are the 1,3,5-triene methyl (Z)-2-isopropylidene-3,4,5-tris(methoxycarbonyl)-6-methylhepta-3,5-dienecarboxylate (14), the allyl alcohol dimethyl (Z)-2-(1-hydroxy-1-methylethyl)but-2-enedicarboxylate (15), the 1,3-diene dimethyl (Z)-2-isopropenylbut-2-enedicarboxylate (16), and the allyl ether dimethyl 2-isopropylidene-3-methoxysuccinate (17). The formation of most of these side products is interpreted as the reaction of a vinyl carbenoid species with O-...

Base-induced reaction of 2,6-dimethylpyridine (2,6-lutidine) (1) with two equivalents of various ketones has been reported to provide C-2-symmetrical pyridine diols 3. Closer examination reveals that competitive di-addition to a single methyl group can occur providing C-s-symmetrical pyridine diols 7. By varying the lithiation times, the formation of this side product could be maximized or minimized on the basis of a mechanistic proposal for the competing pathways. The formation of the C-s-diol 7 could be excluded completely by using potassium diisopropylamide as base; high yields of C-2-symmetrical pyridine diols 3 are obtained. Regioselective additions of 1 to (R)-fenchone and (-)-menthone were also achieved.

A novel [3.3]sigmatropic rearrangement of in situ formed α,β-unsaturated Fischer acyloxy carbenes forming alkynol esters is described. For example, reaction of tetramethylammonium pentacarbonyl(1-oxo-2-butenyl)chromate(1-) (4) with 4-methoxybenzoyl chloride gave 2-methyl-3-butyn-2-yl 4-methoxybenzoate (8) in 32% yield. In addition to the rearrangement products, dienol esters formed by a formal β-hydride elimination-reductive elimination sequence were usually isolated. In the above example, 3-methylbuta-1,3-dien-1-yl 4-methoxybenzoate (9) was obtained (16%) as the side product.

Reactions of isatin with chiral α-aminothiols have been studied. With L-cysteine, only decomposition products were formed under various reaction conditions, whereas D- and L-penicillamine afforded mixtures of diastereomeric 4'-carboxy-5',5'-dimethylspiro[indoline- 3,2'-thiazolidin]-2-ones (4a and 4b or 5a and 5b) in the ratio 1 : 1. The reaction of isatin with methyl L- and D-cysteinates under mild reaction conditions (methanol-benzene, room temperature) proceeded diastereoselectively with the formation of (-)- and (+)-4'-(methoxycarbonyl)spiro[indoline-3,2'-thiazolidin]-2-one (6a and 8) in 38 and 30% yields, respectively. Optically inactive 4'-(methoxycarbonyl)spiro[indoline-3,2'-([2',5']dihydrothiazol)]-2-one (7) was isolated as a side product in 7 and 3% yield, respectively. Structure of the obtained products was determined by spectral methods, including NOE difference measurements and by X-ray crystallography.

The neutral azatricarbaborane 7-t-Bu-arachno-7,1,5,12-NC(3)B(8)H(12), isolated as a side product (yield 2%) from the new synthesis of 7-t-BuNH2-nido-7,8,9-C(3)B(8)H(10) (yield 70%), can be easily converted to the first parent representatives of the 10-vertex nido family of tricarbaboranes, [5,6,9-C(3)B(7)H(10)]- and 5,6,9-C(3)B(7)H(11).

The molecular structure of the title compound, C39H62N2O5Si2, obtained as an unexpected side product, was determined in the course of our studies on the synthesis of N-triisopropyl-1H-indol-3-yl derivatives. Interestingly, although the triisopropylsilyl group was intended as a temporary protecting group, the compound comprises a remarkably stable N—Si bond. The vinyl C=C double bond possesses a Z configuration.

The solid-state reactions of (NH4)2[MS4] (M = W, Mo), [Cu(CH3CN)4](PF6), and bis(diphenylphosphino)methane (dppm) at 110 °C produced pentanuclear clusters [MS4Cu4(dppm)4](PF6)2 (1, M = W; 2, M = Mo), while the analogous solution reaction in CH2Cl2 for M = W yielded a tetranuclear cluster [WS4Cu3(dppm)3](PF6) (3). On the other hand, the (NH4)2[WS4]/CuBr/dppm reaction system resulted in the formation of a tetranuclear cluster [WS4Cu3(dppm)3]Br (4) either in solid at 110 °C or in CH2Cl2, where the solid-state reaction gave also [Cu3(dppm)3Br2]Br (5) as a side product. When the solid-state reactions between (NH4)2[WS4], [Cu(CH3CN)4](PF6) (or CuBr), and dppm were carried out under the presence of [(n-Bu)4N]Br, [WS4Cu2(dppm)3] (6) and [(n-Bu)4N][WS4Cu3Br2(dppm)2] (7) were generated, respectively, while the corresponding solution reactions in CH2Cl2 gave rise to 3 and 4. Compounds 1−7 were fully characterized. 1 crystallizes in the orthorhombic space group Pnma with a = 37.871(6) A, b = 19.667(4) A, c = 14.836(4...

Aus As2O3, SOCl2 und PPh4Cl kann in Acetonitril (PPh4)2[As2Cl8] hergestellt werden. Durch Oxidation mit Chlor entsteht daraus PPh4[AsCl6]. Dieses wurde auch direkt aus Arsen, Chlor und PPh4Cl erhalten, wobei (PPh4)2[As4O2Cl10] · 2 CH3CN als Nebenprodukt entstand; dasselbe wurde in hoher Ausbeute aus AsCl3, As2O3 und PPh4Cl in Acetonitril erhalten. Durch Addition von PPh4Cl entstand daraus (PPh4)2[As2OCl6] · 3 CH3CN. Nach den Rontgenstrukturanalysen kristallisieren beide Produkte triklin (Raumgruppen P 1). Das [As4O2Cl10]2–-Ion kann als zentrosymmetrisches Assoziationsprodukt von zwei Molekulen Cl2AsOAsCl2 und zwei Cl–-Ionen beschrieben werden, wobei jedes Cl–-Ion an alle vier As-Atome koordiniert ist. Im [As2OCl6]2–-Ion sind die beiden As-Atome uber das O-Atom und zwei Cl-Atome miteinander verbunden. The Chlorooxoarsenates(III) (PPh4)2[As4O2Cl10] · 2 CH3CN and (PPh4)2[As2OCl6] · 3 CH3CN (PPh4)2[As2Cl8] can be prepared from As2O3, SOCl2 and PPh4Cl in acetonitrile. Its oxidation with chlorine yields PPh4[AsCl6]. This was also obtained directly from arsenic, chlorine and PPh4Cl, (PPh4)2[As4O2Cl10] · 2 CH3CN being a side product; the latter was obtained with high yield from AsCl3, As2O3 and PPh4Cl in acetonitrile. By addition of PPh4Cl it was converted to (PPh4)2[As2OCl6] · 3 CH3CN. According to their X-ray crystal structure analyses, both crystallize in the triclinic space group P 1. The [As4O2Cl10]2– ion can be regarded as a centrosymmetric association product of two Cl2AsOAsCl2 molecules and two Cl– ions, each Cl– ion being coordinated with all four As atoms. In the [As2OCl6]2– ion the As atoms are linked via the O atom and two Cl atoms.

After prolonged refluxing of 19-tosyloxy-16α,17α-cyclohexanopregn-5-en-3β-ol-20-one (3) with NaI in 2-propanol, the initially formed 19-iodo derivative (4) undergoes supraface migration of the CH2I group from the C(10) atom to the C(6) atom, probably through involvement of a homoallyl cation. The resulting 6β-iodomethyl-16α,17α-cyclohexano-19-norpregn-5(10)-en-3β-ol (5) was transformed in three steps into 6α-methyl-16α,17α-cyclohexano-19-norprogesterone (6α-methyl-19-nor-D′6-pentarane,8). The transformation of compound5 into the target product8 also gave a side product, a pentarane with aromatic ringA (10), which was isolated and characterized by spectroscopic methods.

The amine elimination reaction of Me2Si(1-indenyl)2 (1, (SBI)H2) and Hf(NMe2)4 (2) affords rac-Me2Si(η5-1-indenyl)2Hf(NMe2)2 (rac-3, rac-(SBI)Hf(NMe2)2) in 20% isolated yield. This reaction proceeds by initial formation of a mono(indenyl) intermediate, (η5-C9H6SiMe2C9H7)Hf(NMe2)3 (4), which reacts reversibly with a second equivalent of 2 to form a binuclear complex, {μ-η5:η5-Me2Si(1-indenyl)2}{Hf(NMe2)3}2 (5), and undergoes reversible intramolecular amine elimination to form rac-3 and meso-3. The novel C1-symmetric ansa-metallocene {Me2Si(η5-1-indenyl)(η3-2-indenyl)}Hf(NMe2)2 (6), in which one of the indenyl groups is bridged through the 2-position, is observed as a side product in the synthesis of 3. Complex 6 has been prepared in 21% isolated yield by thermolysis of 4 (or mixtures of 1 and 2) at 160 °C and can be converted to {Me2Si(η5-1-indenyl)(η3-2-indenyl)}HfMe2 (7, 100% NMR) by reaction with AlMe3. The molecular structures of rac-3 and 6 have been determined by X-ray crystallography.

2-(Trimethylsiloxy)phenyl isocyanide (1) reacts with trans-[ReCl(N2)(dppe)2] (dppe = 1,2-bis(diphenylphosphino)ethane) in boiling THF to give trans-[Re(Cl)(CNC6H4-2-OSiMe3)(dppe)2] (3). In boiling CH2Cl2 the same reaction proceeds with Si−O bond cleavage to yield trans-[Re(Cl)(CNC6H4-2-OH)(dppe)2] (4). Si−O bond cleavage was also observed in the reaction of 2,6-bis(trimethylsiloxy)phenyl isocyanide (2) with trans-[ReCl(N2)(dppe)2] in boiling CH2Cl2, which yields trans-{Re(Cl)[CNC6H3(OH)2-2,6](dppe)2} (5). The Re(II) complex trans-[ReCl2(dppe)2] (6) was isolated as a side product in the above reactions. The complex mer-[ReCl3(NCCH3)(PPh3)2] reacts with 1 in CH2Cl2 to give the isocyanide complex mer-[ReCl3(CNC6H4-2-OH)(PPh3)2] (7). Complex 7 was shown by X-ray crystallography to crystallize with two molecules of chloroform per asymmetric unit. Reaction of fac-[Re(O)Cl3(SMe2)(OPPh3)] with 2 equiv of 1 leads to a Re(V) diisocyanide complex which upon Si−O bond cleavage gives the dicarbene complex fac-{Re(O)Cl...

We describe the first example of manganese(III)-catalyzed aerobic dehydrogenative cyclization producing ring-fused indole skeletons. This catalytic system converts from two C–H bonds of indole and malonate to a C–C bond and produces water as the sole side product. This operationally easy method was extended to an intermolecular cross-dehydrogenative coupling of indole and α-substituted malonate with complete C2-selectivity.

In one-pot catalytic reactions phenylsilane was converted to dithiolato ethers (V–XIV) via hydrosilylation and SiS bond-forming reactions by RhCI(PPh3)3. The reaction of phenyl acetylene, phenylsilane and ArSH (Ar = Ph, o-tolyl, p-tolyl) in 1 : 1 : 2 ratio in the presence of RhCI(PPh3)3 (l mole%) gave RCH2CH2Si(SAr)2 and ethylbenzene as a side product. Similar RhCI(PPh3)3 catalysed reactions of RC≡CH, PhSi3, ArSH (Ar = phenyl, p-tolyl, o-tolyl) (1 : 1 : 2 ratio) gave RCHCHSi(SAr)2 in excellent yields ( > 80%).

The reduction of aryl aldehydes and ketones in neutral medium, to the corresponding hydrocarbons via carbon-nitrogen bond cleavage of the intermediate N-(arylmethyl)anilines with low-valent titanium reagents is described. It provides a mild, convenient and selective pathway for deoxygenation of carbonyls without the production of any side product.

1,3-Diether derivatives of tert-butylcalix[4]arene can be selectively nitrated at the para-position of the phenolic units. In this way clix[4]arenes bearing tert-butyl and nitro groups at the upper rim in alternating sequence are easily available in yields up to 75% Ipso-attack may also occur ortho to the phenolic hydroxy group leading in a side reaction to macrocyclic compounds with two 6-nitrocyclohexa-2,4-dienone units. Both types of structures were established by single crystal X-ray analysis.

The first observed side product, C32H21NO2, in the Sonogashira coupling reaction is reported. The molecular packing shows a high degree of π-stacking interactions in the solid state.

Depolymerization reactions of organostibonic acids with protic ligands have been investigated. Reaction of arylstibonic acids with 8-hydroxyquinoline (8-HQ), or {2-[1H-pyrazol-5(3)-yl]naphthalene-1-ol} (H(2)naphpz) in a 1 : 1 stoichiometry in refluxing toluene affords adamantane-like L(4)(RSb)(4)O(6) clusters [(p-XC(6)H(4)Sb)(4)(O)(6)(Q)(4)] (where X = Cl (1), Br (2), QH = 8-hydroxyquinoline), [(p-ClC(6)H(4)Sb)(4)(O)(6)(Hnaphpz)(4)]·H(2)naphpz (3) and [(p-Br-C(6)H(4)Sb)(4)(O)(6)(Hnaphpz)(4)](2)·H(2)naphpz (4). Further a tetrameric organoantimony oxo cluster, L(4)(RSb)(4)O(4) [(p-ClC(6)H(4)Sb)(4)(O)(4)(naphpz)(4)] (5) has also been isolated as a side product in the reaction of arylstibonic acid with naphthylphenolic pyrazole. Interestingly 1-4 structurally resemble the dimeric form of the antimony oxide Sb(2)O(3) and its mineral senarmontite.

Bulky Grignard reagents possessing a β-hydrogen atom react poorly with formation of an α-branched α-silylamine (XI) as side product, generated via hydride transfer.

Sodium salt of 2'-deoxy-N6-dimethylaminomethylene-3'-O-(tetrahydro-2H-pyran-2-yl)adenosine (VIII) reacted with dibenzyl p-toluenesulfonyloxymethanephosphonate (Ia) to give dibenzyl ester of 2'-deoxy-N6-dimethylaminomethylene-5'-O-phosphonomethyl-3'-O-(tetrahydro-2H-pyran-2-yl)adenosine (XI) which after deprotection afforded the final 2'-deoxy-5'-O-phosphonomethyladenosine (XII). 2'-Deoxy-5'-O-hydroxymethanephosphonyladenosine (XIV) and 5'-O-benzyloxymethanephosphonyl-2'-deoxyadenosine (XIII) were isolated as a side product. The preparation of 2'-deoxy-5'-O-phosphonomethylguanosine (XVI) and protection of the starting nucleoside were analogous to those of compound XII. In the 2'-deoxy-3'-O-phosphonomethylnucleosides series, 2'-deoxy-3'-O-phosphonomethylcytidine (XXI) and 2'-deoxy-3'-O-phosphonomethyladenosine (XXVII) were prepared, using N4-benzoyl-5'-O-tert-butyldiphenylsilyl-2'-deoxycytidine (XVIII) and 5'-O-tert-butyldiphenylsilyl-2'-deoxy-N6-dimethylaminomethyleneadenosine (XXIV), respectively, as starting compounds.