Alkylidene malonitriles

The palladium-catalyzed reaction of 1 1 mixture of allyl chloride 11 and allyl stannane 3a with alkylidene malonitriles e.g., 4a resulted into the double-allylated product 95 (Scheme 29) [33]. The mechanism of this reaction is... 

Oxiranes may also be prepared by the cooxidation of aldehydes and olefins. There are two assumptions as regards the mechanism the oxidation occurs via either an acylperoxy radical or a peracid. The peracid oxidation is stereospecific. Experiments carried out with a view to assessing the radical versus nonradical mechanism indicate that the extent of the radical epoxidation depends on the structure of the olefin and the olefin/aldehyde ratio. Cooxidation in the presence of oxygen was achieved by irradiating the aldehyde and carrying out the reaction with the alkene after a suitable quantity of peracid had been obtained. Enantioselective epoxidation has been described in the reaction of (1-phenyl-alkylidene)malonitriles 63 catalyzed by optically active tertiary amines. ... 

An additional product, 2,6-diphenyl-l-cyanomethylidene-4-dicyanomethylidene-4H-tellunn (11% yield m.p. 259-262°) was isolated from the reaction of the 2,6-diphenyl-4-oxo-4//-tellurin and malonitrile. 4-Oxo-4//-tellurins also condensed with 4-alkylchalcogenium salts to yield 4-alkylidene-4//-tellurins ... 

Malonitrile did not condense with the 4-oxo-4//-l-benzotellurin diacetate to give a 4-alkylidene derivative. Instead, the diacetate was reduced to the 4-oxo-4/f-l-benzotellurin. ... 

A correction has been made to the proposed structure for the product of Knoevenagel condensation of malononitrile with 2-ethoxycarbonylcyclo-hexanone. The product is not the alkylidene malononitrile (121), but is the pyridine (122), although the malonitrile (121) is definitely a precursor. 

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