Rearrangements copper chloride

The reaction of norbomene yields the cis exo diester (equation 66).93 This exo isomer is not obtained directly by Diels-Alder chemistry. Other cyclic alkenes such as cyclopentene yield cis diesters, but isomers are obtained as a result of (3-hydride elimination-readdition from intermediates such as (23) prior to CO insertion (equation 67). Thus the palladium walks around the ring to some extent, but always stays on the same face. The extent of rearrangement can be minimized by higher CO pressures since CO insertion becomes more competitive with (3-elimination. This rearrangement becomes a critical problem in the dicarboxylation of 1-alkenes, since a variety of diesters are formed and the reaction is not particularly useful. These reactions were carried out with catalytic amounts of palladium and stoichiometric amounts of copper chloride. 

ABSTRACT. Lithiumthiazoles react by substitution or addition with gold and copper chlorides and subsequent protonation or alkylation affords stable mono- or bis(carbene) complexes. Complications which occur during these syntheses include homoleptic rearrangement, dissociative polymerization and carbon-carbon ligand coupling. 

In addition to the methods described above, prenol (51) can be prepared from methyl-butynol (43) by rearrangement to prenal (52) using a titanium alkoxide/copper chloride catalyst [69, 70] followed by selective hydrogenation using a ruthenium rhodium tris( 7-sulfonatoyl)phosphine trisodium salt (TPPTS) catalyst [71, 72]. However, it is more usual to prepare the prenyl esters by nucleophilic substitution of a carboxylate anion on prenyl chloride [503-60-6] (56) which, in turn, is available through hydrochlorination of isoprene [78-79-5] (1). This hydrochlorination often employs copper ions as catalysts. These processes are shown in Fig. 8.14. 

Thiazole acid chlorides react with diazomethane to give the diazoketone. The later reacts with alcoholic hydrogen chloride to give chloroacetylthiazole (Scheme 16). However, the Wolff rearrangement of the diazoketone is not consistently satisfactory (82). Heated with alcohol in the presence of copper oxide the 5-diazomethylketone (24) gives ethyl 5-thiazoleacetate (25) instead of the expected ethoxymethyl 5-thiazolyl ketone (Scheme 17) (83). 

The reaction of crotonaldehyde and methyl vinyl ketone with thiophenol in the presence of anhydrous hydrogen chloride effects conjugate addition of thiophenol as well as acetal formation. The resulting j3-phenylthio thioacetals are converted to 1-phenylthio-and 2-phenylthio-1,3-butadiene, respectively, upon reaction with 2 equivalents of copper(I) trifluoromethanesulfonate (Table I). The copper(I)-induced heterolysis of carbon-sulfur bonds has also been used to effect pinacol-type rearrangements of bis(phenyl-thio)methyl carbinols. Thus the addition of bis(phenyl-thio)methyllithium to ketones and aldehydes followed by copper(I)-induced rearrangement results in a one-carbon ring expansion or chain-insertion transformation which gives a-phenylthio ketones. Monothioketals of 1,4-diketones are cyclized to 2,5-disubstituted furans by the action of copper(I) trifluoromethanesulfonate. ... 

The reaction of crotyl bromide with ethyl diazoacetate once again reveals distinct differences between rhodium and copper catalysis. Whereas with copper catalysts, the products 125 and 126, expected from a [2,3] and a [1,2] rearrangement of an intermediary halonium ylide, are obtained by analogy with the crotyl chloride reaction 152a), the latter product is absent in the rhodium-catalyzed reaction at or below room temperature. Only when the temperature is raised to ca. 40 °C, 126 is found as well, together with a substantial amount of bromoacetate 128. It was assured that only a minor part of 126 arose from [2,3] rearrangement of an ylide derived from 3-bromo-l-butene which is in equilibrium with the isomeric crotyl bromide at 40 °C. 

The oxidation of olefins to aldehydes using a palladium chloride-copper(II) chloride catalyst, the Wacker Process, is a well-established industrial reaction. The mechanism of this reaction has not been established in detail, but it most probably involves a cr-7r rearrangement... 

Metal-promoted vinylcyclopropane C3 - C5 ring expansions have been reported. Thus, ethyl 2-methoxy-2-vinylcyclopropanecarboxylate 393 rearranged to a 2 1 mixture of 3-methoxy-2-cyclopentenecarboxylate 396 and 3-methoxy-3-cyclopentene-carboxylate 397 on heating at 160 °C in the presence of catalytic amounts of copper bronze or copper(I) chloride in contrast, platinum and rhodium complexes catalyzed... 

This procedure is adapted from the method of Schlenk and Bergmann.3 Tetraphenylethylene has been prepared by the reaction of diphenylmethane with diphenyldichloromethane 4 by the reaction of diphenyldichloromethane with silver or zinc 4 by the reaction of thiobenzophenone with copper 6 by the reaction of diphenylmethane with sulfur 6 by the reduction of benzophenone with amalgamated zinc in the presence of hydrochloric acid 7 and by the rearrangement of 1,2,2,2-tetraphenylethanol with acetyl chloride.8... 

Benzylmagnesium chloride reacts with methyl vinyl ketone to give a mixture of the 1,4-and 1,2-adducts in the ratio 4 1. Catalysis by copper(I) chloride does not dramatically increase this ratio. For 3-methoxybenzyl-magnesium chloride and the same ketone [Eq. (97)] the ratio of 1,4-adduct 1,2-adduct 1,4-ortho adduct is 2 1 8. Copper catalysis alters this ratio to 15 1 3. Thus copper compounds may be very effective (93) in circumventing the benzylic rearrangement. 

AUcynyl esters are isomerized by silver(I) or cop-per(I) compounds in another [3,3]-sigmatropic rearrangement although the reaction is not of wide synthetic application. Copper(I) chloride requires harsher conditions than AgBp4 to... 

Baeyer-Villiger oxidation, 56, 196, 324, 509 Barium manganate, 23 Barium oxide, 23 Beckmann rearrangement, 472 Benzal chlorides, 465 Benzeneboionic acid, 23-24 7) -Benzenechiomium tricarbonyl, 117 Benzeneselenenic acid, 24 Benzeneselenenic anhydride, 2S Benzeneselenenyl bromide, 25-32 Benzeneselenenyl chloride, 25-32 Benzeneseleninic acid, 32 Benzeneseleninic anhydride, 32-34 Benzeneselenocyanate-Copper(II) chloride, 34-35... 

The elementary substance sodium is at ordinary temperatures a soft, white metal. It consists of sodium atoms arranged in a regular structure (Fig. 4-5) similar to that described for copper, but not identical with it. The elementary substance chlorine is a greenish-yellow gas, consisting of diatomic molecules, Gig. Sodium metal will burn in chlorine gas, to give a new substance, which is sodium chloride (com mon salt), with properties greatly different from those of either of the two substances from which it is made. The sodium atoms in the sodium metal which reacted and the chlorine atoms in the chlorine gas which reacted are present in the sodium chloride formed by the reaction, but rearranged and ordered in a new way. 

The rearrangement of propargyl chlorides to chloroallenes occurs stereoselectively in the presence of BU4NCUCI2 (Sch. 28) [62]. Copper(I) dichloride performs as a reagent to deliver chloride, and CuCl might be acting as a Lewis acid to activate the pro-pargylic chloride for elimination. 

Copper(l) carboxylates give esters with primary (including neopentyl without rearrangement), secondary, and tertiary alkyl, allylic, and vinyhc halides7" A simple Sn mechanism is obviously precluded in this case. Vinylic halides can be converted to vinylic acetates by treatment with sodium acetate if palladium(ll) chloride... 

Methylamino-8-azapurine uniquely followed a more complex path. A simultaneous Dimroth rearrangement to 6-amino-9-methyl-8-azapurine (Section C,2) allowed two isomeric amidinotriazoles to be formed, one from each 8-azapurine. 6-Amino-8-azapurine, when set aside in cupric chloride solution, produced the following complex tetrachlorobis-2-[(4-amino-5-carboxamidinium)-l,2,3-triazole]copper +, the structure of which was verified by single-crystal X-ray work. ... 

Vinylic sulfoxides can undergo additive Pummerer rearrangement when they are treated with trichlo-roacetyl chloride and a zinc/copper couple in refluxing ether giving opticdly pure 7-butyrolactone... 

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