Allyl halides conditions

Metallocorroles (M = Cu, Ni or Pd) can also be alkylated under the same conditions as the metal-free corroles23,24 to give the N2i-alkylated products together with a small amount of C3 alkylated product ( f = Pd). Allyl halides or bulky alkyl halides react with nickel corroles also at the 3-position. 

Trichlorosilanc reacts with allyl halides under mildly basic conditions, subsequent treatment with methylmagnesium bromide giving rise to allyl(trimethyl)silanes15-16. 

Palladium complexes also catalyze the carbonylation of halides. Aryl (see 13-13), vinylic, benzylic, and allylic halides (especially iodides) can be converted to carboxylic esters with CO, an alcohol or alkoxide, and a palladium complex. Similar reactivity was reported with vinyl triflates. Use of an amine instead of the alcohol or alkoxide leads to an amide. Reaction with an amine, AJBN, CO, and a tetraalkyltin catalyst also leads to an amide. Similar reaction with an alcohol, under Xe irradiation, leads to the ester. Benzylic and allylic halides were converted to carboxylic acids electrocatalytically, with CO and a cobalt imine complex. Vinylic halides were similarly converted with CO and nickel cyanide, under phase-transfer conditions. ... 

The difference in reactivity between the anions generated from LDA and LHMDS is difficult to rationalize, but nonetheless reproducible. The same effect has been observed with substituted allyl halides and propargyl halides. Instability of the product under the reaction conditions may account for this phenomenon. Thus, for alkylation of allylic and propargylic halides, LHMDS and KHMDS are the bases of choice. 

There are few reports of oxidative addition to zerovalent transition metals under mild conditions three reports involving group 10 elements have appeared. Fischer and Burger reported the preparation of aTT -allylpalladium complex by the reaction of palladium sponge with allyl bromide(63). The Grignard-type addition of allyl halides to aldehydes has been carried out by reacting allylic halides with cobalt or nickel metal prepared by reduction of cobalt or nickel halides with manganese/iron alloy-thiourea(64). 

The development of the Grignard-type addition to carbonyl compounds mediated by transition metals would be of interest as the compatibility with a variety of functionality would be expected under the reaction conditions employed. One example has been reported on the addition of allyl halides to aldehydes in the presence of cobalt or nickel metal however, yields were low (up to 22%). Benzylic nickel halides prepared in situ by the oxidative addition of benzyl halides to metallic nickel were found to add to benzil and give the corresponding 3-hydroxyketones in high yields(46). The reaction appears to be quite general and will tolerate a wide range of functionality. 

Conditions 0.5 mol% of catalyst five- to tenfold molar excess of allyl halide. 

Allylic halides (example 19, Table VII) carbonylate under very mild conditions. An inverse effect of the CO pressure was observed in reaction with Ni(CO)4, CO dissociation being required to allow coordination of the substrate (168). 

Allyl sulphones can be converted to dienes by alkylation and elimination of sulphinic acid under basic conditions (equation 64)105. Several vitamin A related polyenes have been synthesized following this two-step protocol (Table 10)106. The poor leaving-group ability of the arylsulphonyl group requires treatment with strong base for elimination. However, elimination of the allylsulphonyl group takes place readily under palladium catalysis (equation 65)107. Vinyl sulphones can be converted to dienes via Michael addition, alkylation with allyl halides and elimination of sulphinic acid sequence (equation 66)108. 

Allylation.2 Indium also effects addition of allyl halides to carbonyl compounds under mild conditions. 

For the purpose of carrying out carbonyl addition reactions, allylstannanes can be prepared in situ from metallic tin and an allyl halide (Barbier conditions),259 for example, Equation (93).260... 

Tetralone is readily mono- or di-alkylated at the 1-position to the exclusion of O-alky lation with a range of alkylating agents under liquiddiquid two-phase conditions without an added solvent [24], Similarly, it has been reported that anthrone undergoes mono- and di-C-alky lation at the 10-position with propargyl and allyl halides to the almost complete exclusion of O-alkylation [25]. It has been claimed that methyl-ation yields 9-methoxyanthracene [26],... 

Alkynes react with haloethenes [38] to yield but-l-en-3-ynes (55-80%), when the reaction is catalysed by Cu(I) and Pd(0) in the presence of a quaternary ammonium salt. The formation of pent-l-en-4-ynes, obtained from the Cu(I)-catalysed reaction of equimolar amounts of alk-l-ynes and allyl halides, has greater applicability and versatility when conducted in the presence of a phase-transfer catalyst [39, 40] although, under strongly basic conditions, 5-arylpent-l-en-4-ynes isomerize. Symmetrical 1,3-diynes are produced by the catalysed dimerization of terminal alkynes in the presence of Pd(0) and a catalytic amount of allyl bromide [41]. No reaction occurs in the absence of the allyl bromide, and an increased amount of the bromide also significantly reduces the yield of the diyne with concomitant formation of an endiyene. The reaction probably involves the initial allylation of the ethnyl carbanion and subsequent displacement of the allyl group by a second ethynyl carbanion on the Pd(0) complex. 

The phase-transfer catalysed reaction of nickel tetracarbonyl with sodium hydroxide under carbon monoxide produces the nickel carbonyl dianions, Ni,(CO) 2- and Ni6(CO)162, which convert allyl chloride into a mixture of but-3-enoic and but-2-enoic acids [18]. However, in view of the high toxicity of the volatile nickel tetracarbonyl, the use of the nickel cyanide as a precursor for the carbonyl complexes is preferred. Pretreatment of the cyanide with carbon monoxide under basic conditions is thought to produce the tricarbonylnickel cyanide anion [19], as the active metal catalyst. Reaction with allyl halides, in a manner analogous to that outlined for the preparation of the arylacetic acids, produces the butenoic acids (Table 8.7). 

In the carbonylation of allyl halides the highly toxic [Ni(CO)4] catalyst could be replaced by [Ni(CN)2], which yielded [Ni(CN)(CO)jr under the reaction conditions [17]. The cyanotricarbonylnickel(0) anion is a versatile catalyst of carbonylations under phase transfer conditions [18], however, hydroxycarbonylation of allyl chloride proceeds effectively without PT catalysts in a genuine biphasic system, as well. 

Despite the lower reactivity of solvated perfluoroalkylzinc reagents, perfluoroalkyl iodides undergo synthetically useful zinc-mediated reactions under Barbier conditions which often employ ultrasound and co-catalysts. Under these conditions, the zinc reagents are not well characterized and radical intermediates and SET mechanisms are proposed in some cases. Representative examples are presented below and include the ultrasound-promoted, zinc-mediated perfluoroalkylation of various substrates as reported by Ishikawa and coworkers (Scheme 10)123 126. Yields of carbinols could be improved by use of Ti(II) co-catalyst. Ultrasound promoted the coupling of perfluoroalkyl iodides with vinyl and allyl halides in the presence of Pd co-catalysts. 

More reactive electrophiles, such as benzyl and allyl halides, as well as a- or 3-halo-carbonyl compounds, react smoothly with amines, often even at room temperature. Support-bound chloro- and bromoacetamides, for instance, react cleanly with a wide range of aliphatic and aromatic amines to yield glycine derivatives (Entries 1-4, Table 10.2 [22-32]). This reaction is usually conducted in DMSO at room temperature (2-12 h), but for sensitive amines DMF or NMP might offer milder reaction conditions (Entry 3, Table 10.2). Higher yields can often be obtained by increasing the reaction temperature and the concentration of the amine. 

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