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A mixture of 10 g of finely powdered anhydrous LiCl, 20 g of powdered anhydrous CuCl (note 1) and 40 g of dry tetrahydrofuran was heated under reflux for 15 min. 

The phenylation of styrene with phenyl Grignard reagents as a hard carbon nucleophile proceeds in 75% yield in the presence of PdCl2, LiCl, and K2CO3 at room temperature to give stilbene (207). Selection of the solvent is crucial and the best results are obtained in MeCN. The reaction can be made catalytic by the use of CuCl2[197]. Methyllithium reacts with styrene in the presence of Pd(acac)2 or Pd(OAc)2 to give /3-methylstyrene (208) in 90% yield[198]. 

Diacetoxylation of various conjugated dienes including cyclic dienes has been extensively studied. 1,3-Cyclohexadiene was converted into a mixture of isomeric l,4-diacetoxy-2-cyclohexenes of unknown stereochemistry[303]. The stereoselective Pd-catalyzed 1,4-diacetoxylation of dienes is carried out in AcOH in the presence of LiOAc and /or LiCI and beiizoquinone[304.305]. In the presence of acetate ion and in the absence of chloride ion, /rau.v-diacetox-ylation occurs, whereas addition of a catalytic amount of LiCl changes the stereochemistry to cis addition. The coordination of a chloride ion to Pd makes the cis migration of the acetate from Pd impossible. From 1,3-cyclohexadiene, trans- and ci j-l,4-diacetoxy-2-cyclohexenes (346 and 347) can be prepared stereoselectively. For the 6-substituted 1,3-cycloheptadiene 348, a high diaster-eoselectivity is observed. The stereoselective cij-diacetoxylation of 5-carbo-methoxy-1,3-cyclohexadiene (349) has been applied to the synthesis of dl-shikimic acid (350). 

It is possible to prepare 1-acetoxy-4-chloro-2-alkenes from conjugated dienes with high selectivity. In the presence of stoichiometric amounts of LiOAc and LiCl, l-acetoxy-4-chloro-2-hutene (358) is obtained from butadiene[307], and cw-l-acetoxy-4-chloro-2-cyclohexene (360) is obtained from 1.3-cyclohexa-diene with 99% selectivity[308]. Neither the 1.4-dichloride nor 1.4-diacetate is formed. Good stereocontrol is also observed with acyclic diene.s[309]. The chloride and acetoxy groups have different reactivities. The Pd-catalyzed selective displacement of the chloride in 358 with diethylamine gives 359 without attacking allylic acetate, and the chloride in 360 is displaced with malonate with retention of the stereochemistry to give 361, while the uncatalyzed reaction affords the inversion product 362. 

In MeOH, l,4-dimethoxy-2-cyclohexene (379) is obtainejl from 1,3-cydo-hexadiene[315]. Acetoxylation and the intramolecular alkoxylation took place in the synthesis of the naturally occurring tetrahydrofuran derivative 380 and is another example of the selective introduction of different nucleo-philes[316]. In intramolecular 1,4-oxyacetoxylation to form the fused tetrahy-drofurans and tetrahydropyrans 381, cis addition takes place in the presence of a catalytic amount of LiCI, whereas the trans product is obtained in its absence[317]. The stereocontrolled oxaspirocyclization proceeds to afford the Irons product 382 in the presence of Li2C03 and the cis product in the presence of LiCl[ 318,319]. 

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]. 

Carbonylation of allylic alcohols requires severe conditions[248]. The carbonylation of allylic alcohols proceeds smoothly in the presence of LiCl and Ti(IV) isopropoxide[249j. The allylic methyl ether 394 can be carbonylated with the use of PdCl2[250] or 7r-allylpalladium coordinated by BF4, PF, and... 

Similarly to alkenes. alkynes also insert. In the reaction of 775 carried out under a CO atmosphere in AcOH, sequential insertions of alkyne, CO. alkene. and CO take place in this order, yielding the keto ester 776[483]. However, the same reaction carried out in THF in the presence of LiCl affords the ketone 777, but not the keto ester[484]. The tricyclic terpenoid hirsutene (779) has been synthesized via the Pd-catalyzed metallo-ene carbonylation reaction of 778 with 85% diastereoselectivity as the key reaction[485], Kainic acid and allo-kainic acid (783) have been synthesized by the intramolecular insertion ol an alkene in 780, followed by carbonylation to give 781 and 782[486],... 

Butyrolactones are prepared by intramolecular reaction of haloallylic 2-alkynoates. The a-chloromethylenebutyrolactone 301 is prepared by the intramolecular reaction of300[150,151]. 4 -Hydroxy-2 -alkenyl 2-alkynoates can be used instead of haloallylic 2-alkynoates, and in this reaction, Pd(II) is regenerated by elimination of the hydroxy group[152]. As a related reaction, the q-(chloromethylene)-7-butyrolactone 304 is obtained from the cinnamyl 2-alkynoate 302 in the presence of LiCl and CuCbflSS]. Isohinokinin (305) has been synthesized by this reaction[l 54]. The reaction is explained by chloro-palladation of the triple bond, followed by intramolecular alkene insertion to generate the alkylpalladium chloride 303. Then PdCb is regenerated by attack of CuCb on the alkylpalladium bond as a key step in the catalytic reaction. 

Standard Heck conditions were used to introduce the dchydroalanine side-chain with 4-bromo-3-iodo-l-(4-methylphenylsulfonyl)indole[12]. Using 4-fluoro-3-iodo-l-(4-methylphenylsulfonyl)indole as the reactant, Merlic and Semmelhack found that addition of 2 eq, of LiCl or KCl improved yields in reactions carried out with 10% Pd/C as the catalyst[13]. The addition of the dehyroalanine side chain can also be done by stoichiometric Pd-mediated vinylation (see Section 11.2). A series of C-subslituled dehydro tryptophans was prepared in 40-60% yield by this method[14]. 

Trifluoromethanesulfonyloxy Methyl a-acetamidoacrylate, PdlOAclj, n-Bu N, LiCl, feis-(diphenylphosphinoferrocene) 38 [8]... 

The practical problems He ia the separatioa of the chlorine from the hydrogea chloride and nitrous gases. The dilute nitric acid must be reconcentrated and corrosion problems are severe. Suggested improvements iaclude oxidation of concentrated solutions of chlorides, eg, LiCl, by nitrates, followed by separation of chlorine from nitrosyl chloride by distillation at 135°C, or oxidation by a mixture of nitric and sulfuric acids, separating the... 

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