Acid cyanides palladium-catalyzed

Condensation of 1 with 3,4-dimethoxybenzyl cyanide afforded the epimeric cyano alcohols 2, which on alkaline hydrolysis gave the epimeric y -lactones 3 in 64% yield. Treatment of 3 with crotyl bromide afforded the a,a-disubstituted lactone 4. Acid-catalyzed debenzy-lation of 4 afforded the alcohol 5, which on sequential saponification, periodate cleavage and reduction gave the lactone 7 via 6. Palladium-catalyzed oxidation of 7 afforded 8, which underwent intramolecular cyclization to produce 9 in 66% yield. Treatment of 9 with methylamine gave 10 (41%) and 11 (7%) however, the former can be cyclized into the latter in 85% yield. Reduction of 11 furnished 12 in 77% yield. 

Bulky imidazolium salts 76 and 77 were found to greatly accelerate the amination of aryl chlorides using nickel catalysts <01TL5689> and palladium catalysts <01JOC7729>. to be useful ligands in the palladium-catalyzed a-arylation of esters and protected amino acids <01JACS8410>, to be catalytic, environmentally benign solvents for the cyanide displacement... 

This palladium-catalyzed coupling mediated by norbornene has also been conducted with aryl halides containing an ortho substituent in the presence of a coupling partner, such as cyanide (Equation 19.155). In this case, tihe product does not contain the nor-bomene additive. Various coupling partners include cyanide, olefins, allylic alcohols, diphenyl- and alkylphenylacetylenes, arylboronic acids, hydrogen donors, and amides. The proposed mechanism (Scheme 19.20) begins with the oxidative addition of Pd(0)... 

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. ... 

Because of its low acidity, hydrogen cyanide seldom adds to nonactivated multiple bonds. Catalytic processes, however, may be applied to achieve such additions. Metal catalysts, mainly nickel and palladium complexes, and [Co(CO)4]2 are used to catalyze the addition of HCN to alkenes known as hydrocyanation.l67 l74 Most studies usually apply nickel triarylphosphites with a Lewis acid promoter. The mechanism involves the insertion of the alkene into the Ni—H bond of a hydrido nickel cyanide complex to form a cr-alkylnickel complex173-176 (Scheme 6.3). The addition of DCN to deuterium-labeled compound 17 was shown to take place... 

Hydrocyanation is the formal addition of hydrogen cyanide to alkenes. alkynes, and dienes to yield nitriles. These reactions can be catalyzed by various copper, cobalt, nickel and palladium catalysts modified with phosphanes and phosphites and/or Lewis acids. Hydrocyanation of carbonyl groups in aldehydes and ketones is covered in Section D.l.3.7. 

The nickel/Lewis acid binary catalyst system can be used with carbonyl cyanides. It effectively catalyzes intermolecular addition reactions that are difficult to execute using a palladium catalyst (Eq. (6.22)) [61]. 

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