Cyanomethyl anion addition

Comparing the process of electrochemical activation to standard base-promoted addition of sulfur, the ylidene sulfur adduct 12 is formed by addition of a S -cyanomethyl anion onto t ano group (Scheme 9), while in the previous version the poly sulfide-like anion affects the methylene group of the a,p-unsaturated nitrile 10 (Scheme 8). However, if the activation with sulfur does not occur properly, the ylidene-sulfur adduct of presumed structure 10 or 12 is not formed and the side-reaction takes place. 

Additions to quinoline derivatives also continued to be reported last year. Chiral dihydroquinoline-2-nitriles 55 were prepared in up to 91% ee via a catalytic, asymmetric Reissert-type reaction promoted by a Lewis acid-Lewis base bifunctional catalyst. The dihydroquinoline-2-nitrile derivatives can be converted to tetrahydroquinoline-2-carboxylates without any loss of enantiomeric purity <00JA6327>. In addition the cyanomethyl group was introduced selectively at the C2-position of quinoline derivatives by reaction of trimethylsilylacetonitrile with quinolinium methiodides in the presence of CsF <00JOC907>. The reaction of quinolylmethyl and l-(quinolyl)ethylacetates with dimethylmalonate anion in the presence of Pd(0) was reported. Products of nucleophilic substitution and elimination and reduction products were obtained . Pyridoquinolines were prepared in one step from quinolines and 6-substituted quinolines under Friedel-Crafts conditions <00JCS(P1)2898>. 

Ethyl-2-(sulfonylmethyl)- and 2-(cyanomethyl)-allyl carbonates133 as well as (methoxycarbo-nyl)methylallyl carbonates136 serve as substrates for the [3 + 2] cycloaddition. Oxidative addition into the allylic C—O bond of the carbonate, followed by decarboxylation, gives a 2-substituted allylpalladium al-koxide. The alkoxide then deprotonates the C—H a to the electron-withdrawing substituent at the 2-position of the allyl. This anion then undergoes a Michael addition to an a,(3-unsaturated ketone or ester, followed by intramolecular allylation of the anion of the Michael product (Scheme 2). 

With 3-methylcinnamonitrile (entry 2), hydrodimerization was the main pathway followed, whereas acrylonitrile (entry 3) afforded the best yields of cyanomethylated product under conditions similar to those observed for cinnamonitrile. Efforts to accomplish the Michael addition of CH2CN to acrylonitrile, with the anionic reagent obtained via deprotonation of MeCN by electro reduced azobenzene (entry 4), gave glutaronitrile in low yields but no adiponitrile (hydrodimerization product). Anionic polymerization of acrylonitrile was the main reaction pathway. 

Previous sections have detailed numerous examples where ultrasound has been used to activate a metal surface. Reaction with species in solution then provides a rapid route to a variety of organometalhc products. However, these effects are not confined to organometalhc systems and there are already a number of examples where inorganic bases can be used under heterogeneous conditions in wholly organic reactions. Shibata and-co-workers [200] have described the cyanomethylation of a variety of chalcones by Michael addition of the anion derived from acetonitrile. Sonolysis for 15 min in the presence of KO2 gave the adducts (44) as the major product in each case (Scheme 93). 

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