Benzene, chromium complex

CJU, Benzene, chromium complex, 21 1, 2 CjH, 1,3-Cyclohexadiene, ruthenium complex, 21 77... 

But-2-yne undergoes cyclic condensation when reacted with triphenylchro-mium(III) tetrahydrofuranate to yield hexamethylbenzene and bis-hexamethyl-benzene-chromium complex in the same reaction 1,2,3,4-tetramethylnaphthalene... 

QHt, Benzene chromium complex, 21 1, 2 ruthenium complex, 22 177 CftHs, 1,3-Cyclohexadiene ruthenium complex, 21 77 22 177 C7H,0, 1,3-Cycloheptadiene ruthenium complex, 22 179 C,Hs, Benzene, ethynyl- ruthenium complex, 21 82 C H, Benzene, vinyl- ruthenium complex, 21 80... 

In addition, random co-polymers 90 derived from [l]ferrocenophanes and silicon-bridged bis(benzene)chromium complexes have been synthesized (Equation (36)). ... 

CgHjN, Pyridine, osmium complex, 26 291 CgHjNOj, 4-Pyridinecarboxylic acid, rhodium complex, 27 292 CgHg, Benzene, chromium complex, 28 139 QHgO, Phenol, rhodium complex, 27 292 CgHgS, Benzenethiol, osmium complex. 26 304... 

Miscellaneous.- New optically active phosphites (103) and (104) derived from R- or 5-2,2 -binaphthol have been prepared by standard methods and used as ligands for asymmetric hydroformylation or hydrocyanation reactions. Low to moderate asymmetric induction was achieved in the synthesis of S,6-disubstituted cyclohexadienes from benzene chromium complexes when the optically active phosphites (105) were ligands. ... 

C5H5NO2, 4-Pyridinecarboxylic acid, rhodium complex, 27 292 C Hg, Benzene, chromium complex,... 

In a related study, Uemura and co-workers obtained planar-chiral isochromene chromium complexes by gold-catalyzed enantioselective cyclization of prochiral (l,3-dihydroxymethyl-2-alkynyl)benzene chromium complexes. " The highest selectivities in this 6-e <3to-dig-hydroalkoxylation were observed in the presence of a chiral cationic gold catalyst prepared in situ from (/ )-xylyl-BINAP(AuC1)2 and AgSbFs. With (/ )-SEGPHOS(AuCl)2 and AgBp4, the enantiomeric product was obtained, albeit with low enantioselectivity. 

Representative procedure for the enantioselective gold-catalyzed cyclization of (I,3-dihydroxymethyl-2-alkynyl)benzene chromium complexes. (R -Tricarbonyl-(3-methyl-5-hydroxymethyl-lH-isochromene)chromiunP ... 

The asymmetric cross-coupling of the meso-tricarbonyl (ortho-dichloro-benzene)chromium complex with a wide range of vinylic metals in the... 

In a rather different approach optically active chromium complexes of 2,3-dihydro-1 H-in-denone are used as chiral enolate precursors. These chiral complexes react with 3-buten-2-one in benzene using l,5-diazabicyclo[4.3.0]non-5-ene as the base. The diastereomeric ratio of the product is the same irrespectively of whether the exo- or the Noisomer of the chromium... 

Chromium, (ri6-benzene)tricarbonyl-stereochemistry nomenclature, 1,131 Chromium complexes, 3,699-948 acetylacetone complex formation, 2,386 exchange reactions, 2,380 amidines, 2,276 bridging ligands, 2,198 chelating ligands, 2,203 anionic oxo halides, 3,944 applications, 6,1014 azo dyes, 6,41 biological effects, 3,947 carbamic acid, 2,450 paddlewheel structure, 2, 451 carboxylic acids, 2,438 trinuclear, 2, 441 carcinogenicity, 3, 947 corroles, 2, 874 crystal structures, 3, 702 cyanides, 3, 703 1,4-diaza-1,3-butadiene, 2,209 1,3-diketones... 

Among the compounds that form complexes with silver and other metals are benzene (represented as in 9) and cyclooctatetraene. When the metal involved has a coordination number >1, more than one donor molecule participates. In many cases, this extra electron density comes from CO groups, which in these eomplexes are called carbonyl groups. Thus, benzene-chromium tricarbonyl (10) is a stable compound. Three arrows are shown, since all three aromatic bonding orbitals contribute some electron density to the metal. Metallocenes (p. 53) may be considered a special case of this type of complex, although the bonding in metallocenes is much stronger. 

First stable phosphaquinoid compounds, diphosphaquinones 1 were synthesized by dechlorination of l,4-bis(chlorophosphino)benzene and isolated as chromium complexes (Scheme 6) [8],... 

Bis(benzene)chromium(0) is easily oxidized, and mixed complexes are obtained by means of substitution reactions. For example,... 

Another example of an unusual reaction occurring in the gas phase is ammonia in a chromium complex ion being substituted by arenes such as benzene (4). It is important to note the uncommon oxidation state of the chromium. 

According to Widdowson, [(methoxymethoxy)benzene]tricarbonylchromium (448) was deprotonated with enantiotopos differentiation by n-BuLi/(—)-sparteine (11), and the lithium intermediate 449 was trapped by various electrophiles to give the products 451 with ee values up to 97% (equation 122) . Surprisingly, opposite enantiomers are formed when stoichiometric or excess amounts of base are applied. The authors presume that in the dilithium intermediate 450 the C—Li bond (in the rear) has a higher reactivity than the other one (pointed to the front). The deprotonation procedure was also applied to a couple of 1,4-disubstituted chromium complexes . 

One of the most useful types of 7r-complexes of aromatic compounds from the synthetic point of view are chromium complexes obtained by heating benzene or other aromatics with Cr(CO)6. 

A second synthetic procedure for preparing silylated arene complexes, based on the metalation of a preformed rj6-arene complex, followed by treatment with an organochlorosilane, has been used only in one case so far namely, bis(benzene)chromium (47) ... 

The traditional names ferrocene, manganocene, ruthenocene, nickelocene, etc. are given to the respective bis(ri5-cyclopentadienyl)metal complexes. Ocene names should not be coined for isoelectronic species such as chromocene for bis(ri6-benzene)chromium, for structurally analogous... 

Ten grams of Bis (benzene) chromium (0) are added to a mixture of 200ml benzene and 100ml water contained in a 500ml auction flask which ia fitted with a stopper and an inlet tube that reaches almost to the bottom of the vessel. Air ia drawn through the flask until the complex has dissolved and the benzene layer has become practically colorless. The yellow-brown aqueous layer ia separated and filtered if necessary. It ia then treated with a aaturated solution of potassium iodide until no more precipitate forms. After cooling in ice the yellow product is filtered off, washed three times with 5ml of 95% alcohol, and finally with ether. The compound is dried in vacuo. 

Fluorine atoms in electron-deficient benzene derivatives, such as l-fluoro-2-nitroben-zene,149-150 l-fluoro-4-nitrobenzene.151 153 2-fluorobenzaldchyde,154"156 2-fluoroaceto-phenone,155156 4-fluoroacetophenonc,157 2-fluorobenzophenone.156 2- and 4-fluorobenzoni-trile,158 and 4-fluorophenyl trifluoromethyl sulfone,152,159 are easily substituted by N-nucleophiles. Even fluorine in electron-deficient sandwich complexes, such as tricarbonyl(t/6-fluoro-benzene)chromium (3), is substituted by amines.160161... 

Arene(tricarbonyl)chromium complexes, 19 Nickel boride, 197 to trans-alkenes Chromium(II) sulfate, 84 of anhydrides to lactones Tetrachlorotris[bis(l,4-diphenyl-phosphine)butane]diruthenium, 288 of aromatic rings Palladium catalysts, 230 Raney nickel, 265 Sodium borohydride-1,3-Dicyano-benzene, 279 of aryl halides to arenes Palladium on carbon, 230 of benzyl ethers to alcohols Palladium catalysts, 230 of carboxylic acids to aldehydes Vilsmeier reagent, 341 of epoxides to alcohols Samarium(II) iodide, 270 Sodium hydride-Sodium /-amyloxide-Nickel(II) chloride, 281 Sodium hydride-Sodium /-amyloxide-Zinc chloride, 281 of esters to alcohols Sodium borohydride, 278 of imines and related compounds Arene(tricarbonyl)chromium complexes, 19... 

Bis(azidomethyl)oxetane, 1896 Bis(azidothiocarbonyl) disulfide, 1012a Bis(benzeneazo) oxide, 3484 Bis(jj-benzene)chromium(0), 3505 Bis(benzene)chromium dichromate, 3845 Bis(benzenediazo) sulfide, 3485 Bis(jj-benzene)iron(0), 3506 Bis(benzeneiron)—fulvalenediyl complex, 3828 Bis(jj-benzene)molybdenum(0), 3508... 

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