Halides allyl preparation

In summary, it can be said that the Y-substituted allylphenols can be prepared by Oalkylation of the sodium salt of the phenol in benzene, and —they usually cannot be prepared by the Claisen rearrangement. The condensation of free phenols with allylic halides, allylic alcohols, and dienes may give allylphenols, but frequently yields other products. - 94... 

Polymerization was carried out in benzene in the presence of bis-(7r-allylnickel halides). The latter were prepared from nickel carbonyl and allyl halide (allyl bromide, crotyl chloride, bromide, or iodide etc.). The results of the polymerization runs are reported in Table I. The data indicate that all of the bis(7r-allylnickel halides) initiate by themselves the stereospecific butadiene polymerization yielding a polymer with 97-98% 1,4-units. The cis-l,4/trans-l,4 ratio depends on the halide in the dimeric r-allylnickel halide but not on the nature of allylic ligand. The case of bis(7r-crotylnickel halides) shows the effect of halide on microstructure, for whereas (C4H7NiCl)2 initiates cis- 1,4-polybutadiene formation, trans-1,4 polymers are produced by (C4H7NiI)2. The reactivity increase in the series Cl < Br < I. 

A useful method of preparing 1-alkenes involves reaction of Grignard reagents with the unusually reactive halide, allyl bromide ... 

Cleavage of 2,3-epoxy halidesA zinc-copper couple, prepared by sonication of zinc powder and Cui in aqueous ethanol, cleaves epoxy halides to a radical that rearranges to an allylic alcohol. Since the epoxy halide is prepared by epoxidation of an allylic alcohol (m-chloroperbenzoic acid) followed by reaction with P(ChH5)3 and CBr4, the reaction effects 1,3-transposition of the hydroxyl group. 

Rearrangement of the initial insertion product occurs in the reaction of various vinylic palladium halides with alkenes . The vinylic palladium halides are prepared in situ from vinyl mercurials and palladium halides. The initial insertion products undergo a jS-metal hydride elimination followed by a reverse readdition to form relatively stable n-allylic Pd complexes ... 

The metal center in (i9 -C5H5)M(L)(CO)(allyl) can be considered pseudotetrahedral and characterized by the (R) and (5) nomenclature. Neutral chiral complexes of this type have been prepared previously, e.g., phosphine carbonyl derivatives (21, 75) and nitrosyl halide derivatives prepared by carbonyl displacement from nitrosyl cations by iodide (57, 60). Each of the diastereomers produced by the addition of a prochiral allyl moiety to the chiral metal center exhibit endo-exo isomerism. The endo-exo equilibration depends on charge and the neutral nitrosyl iodides rearrange rapidly compared to the cationic nitrosyls. 

The high regio- and stereoselectivities of the process as well as its tolerance of functional groups underline the potential of the methodology. Its wide synthetic applicability is demonstrated by the preparation of a variety of functionalized heterocycles from readily available alkynes. Aryl and alkenyl halides or triflates, alkynyl halides, allyl and... 

Examples of sohd-bound Pd-catalyzed carbonylation of aryl and alkenyl halide, allyl alcohol, and derivatives are abundant in the literature. Polyketones have been obtained via carbonylation of ethylene and carbon monoxide catalyzed by palladium complexes of polysiloxane-bound phosphinet t or Pd(dppp) absorbed on alumina.f f Similar processes can also be carried out by catalyst formed simply by absorbing Pd(02CNEt2)2(NHEt2)2 onto silica geL Polyphosphine-bound palladium has been used to prepare ethyl hexanoate from 1-pentene, CO, and ethanol. Similar esterification of styrene has been achieved using a bimetallic system involving palladium and nickel immobilized on poly(Af-vinyl-2-pyrrolidone).f ... 

Allyl halides are probably the most common allylic reagents used. Palladium complexes with not only simple 77 -allylic moieties, but also cyclic derivatives, t/ -benzyls, 77 -allylic complexes derived from morphine alkaloids, and trialkyltin-subtituted T/ -allyls have been synthesized by oxidative addition of appropriate halides. Allyl carboxylates, especially acetates, are also common. When combined with other fimctionalities in the substrate, they lead to functionalized T/ -allylic Pd complexes. Examples of ester-substituted T/ -allyls obtained by reaction of the corresponding allylic trifluoroacetates 88 have been reported. Palladium complexes that bear an 7 -allyl with a pendant 2-pySiMc2-, where the py group coordinates to Pd, have been prepared from the corresponding allylic acetates 89. Allyl carbonates are also commonly used both in the stoichiometric preparation of -allylic complexes and in catalytic reactions that proceed through Pd -allylic intermediates. ... 

Aldehydes can also be prepared by the carbonylation of aryl and alkenyl halides and triflate, and benzyl and allyl chlorides using tin hydride as a hydride source and Pd(PhjP)4 as a catalyst[377]. Hydrosilancs arc used as another hydride source[378]. The arenediazonium tetralluoroborate 515 is converted into a benzaldehyde derivative rapidly in a good yield by using Et ,SiH or PH MS as the hydride source[379]. 

Aryl halides react with a wide variety of aryl-, alkenyl- and alkylstan-nanes[548-550]. Coupling of an aryl tritlate with an arylstannane is a good preparative method for diaryls such as 688. The coupling of alkenylstannanes with alkenyl halides proceeds stereospecifically to give conjugated dienes 689. The allylstannane 690 is used for allylation[397,546,551-553]. Aryl and enol triflates react with organostannanes smoothly in the presence of LiCl[554]. 

Perfluoroalkylzinc iodides, prepared in situ from iodides and ultrasonically dispersed Zn, are coupled with allylic halides via an allylic rearrangement[271]. The Pd-catalyzed homocoupling of allylic acetate in the presence of Zn to give a mixture of regioisomers 416 and 417 may proceed via in situ formation of allylzinc species[272,273]. 

The ( )-vinylsilane 151 was prepared by treatment of the silylstannation product 150 with hydrogen iodide[75] and the silylzincation product with water[70]. The silylstannylation of 1-ethoxyacetylene proceeds at room temperature using Pd(OAc)i and 1,1,3,3-tetramethylbutyl isocyanide regioselec-tively and an Si group is introduced at the ethoxy-bearing carbon. Subsequent Cul- and Pd-catalyzed displacement of the stannyl group in the product 152 with allyl halide, followed by hvdrolvsis, affords the acylsilane 153[79],... 

Cadmium alkyl and aryl halides, RCdX, as weU as cadmium allyls have been prepared by Grignard reactions but, as yet, have not realized any commercially important uses despite reactivity toward a number of organic and inorganic materials. 

This reaction illustrates a stereoselective preparation of (Z)-vinylic cuprates, which are very useful synthetic intermediates. They react with a variety of electrophiles such as carbon dioxide, epoxides, aldehydes, allylic halides, alkyl halides, and acetylenic halides they undergo... 

Methylsuccinic acid has been prepared by the pyrolysis of tartaric acid from 1,2-dibromopropane or allyl halides by the action of potassium cyanide followed by hydrolysis by reduction of itaconic, citraconic, and mesaconic acids by hydrolysis of ketovalerolactonecarboxylic acid by decarboxylation of 1,1,2-propane tricarboxylic acid by oxidation of /3-methylcyclo-hexanone by fusion of gamboge with alkali by hydrog. nation and condensation of sodium lactate over nickel oxide from acetoacetic ester by successive alkylation with a methyl halide and a monohaloacetic ester by hydrolysis of oi-methyl-o -oxalosuccinic ester or a-methyl-a -acetosuccinic ester by action of hot, concentrated potassium hydroxide upon methyl-succinaldehyde dioxime from the ammonium salt of a-methyl-butyric acid by oxidation with. hydrogen peroxide from /9-methyllevulinic acid by oxidation with dilute nitric acid or hypobromite from /J-methyladipic acid and from the decomposition products of glyceric acid and pyruvic acid. The method described above is a modification of that of Higginbotham and Lapworth. ... 

Differences in solubility of the reactants may for example be utilized as follows. Sodium iodide is much more soluble in acetone than are sodium chloride or sodium bromide. Upon treatment of an alkyl chloride or bromide with sodium iodide in acetone, the newly formed sodium chloride or bromide precipitates from the solution and is thus removed from equilibrium. Alkyl iodides can be conveniently prepared in good yields by this route. Alkyl bromides are more reactive as the corresponding chlorides. Of high reactivity are a-halogen ketones, a-halogen carboxylic acids and their derivatives, as well as allyl and benzyl halides. 

This reaction, which is named after W. Williamson, is the most important method for the synthesis of unsymmetrical ethers 3. For this purpose an alkoxide or phenoxide 1 is reacted with an alkyl halide 2 (with R = alkyl, allyl or benzyl). Symmetrical ethers can of course also be prepared by this route, but are accessible by other routes as well. 

The cyclized analog of meralluride is prepared by a similar synthesis. Thus, condensation of camphoric acid (42) (obtained by oxidation of camphor) with ammonia gives the bicyclic succinimide (44). Reaction with allyl isocyanate followed by ring opening and then reaction with mercuric acetate affords the mercury derivative (45) as the acetate rather than the hydroxide as above. Reaction with sodium chloride converts that acetate to the halide (46). Displacement on mercury with the disodium salt of thioglycollic acid affords the diuretic mercaptomerine (47). ... 

Preparing Alkyl Halides from Alkenes Allylic Bromination 339... 

Another method for preparing alkyl halides from alkenes is by reaction with jV-brotnosuccinimide (abbreviated NBS) in the presence of light to give products resulting from substitution of hydrogen by bromine at the allylic position—the position next to the double bond. Cyclohexene, for example, gives 3-bromo-cyclohexene. 

---