Malonitrile complexation

J0rgensen has also reported a sequential Michael/Michael/aldol condensation for the three component coupling of malonitrile 111 and a,P-unsaturated aldehydes that involves two iminium ion catalysed Michael additions followed by an intramolecular aldol condensation (Scheme 43) [170]. Using diarylprolinol ether 55 (10 mol%) in a concentrated toluene solution of malonitrile 111 and 3 equivalents of a,P-unsaturated aldehyde the reaction products can be isolated in just 1 8 h (57-89% yield 97-99% ee). The atom efficiency of this three component reaction is remarkable and the ability to prepare these complex products under... 

Tetrakis(phenylethynyl)ethene (5) forms jr complexes with 2,4,7-trinitrofluoren-9-one (6) and (2,4,7-trinitrofluoren-9-ylidene)malonitrile (7)24. In the solid state the CT complexes show a 1 2 stoichiometry in solution (CHCI3) the purple-coloured complex between 5 and tetracyanoethylene shows a 1 1 stoichiometry. Such complexes may be of interest as potential new materials e.g. in the field of non-linear optics. 

The unique TEE framework facilitates -conjugation with pendant aromatic substituents by allowing coplanar orientation throughout the molecular core, as was first witnessed in the X-ray crystal structure of tetrakis(phenylethynyl)ethene 1 determined by Hopf and co-workers [9]. In contrast, coplanarity is prevented by steric interactions in molecules such as cis-stilbenes or tetraphenylethene 2 [10] (Figure 2). The planarity makes it possible for 1 to form highly ordered 1 2 stoichiometric donor-acceptor -complexes in the solid state with electron-deficient molecules such as 2,4,7-trinitrofluoren-9-one and (2,4,7-trinitrofluoren-9-ylidene)malonitrile [11]. In solution, relatively weak 1 1 complexes with each of these two acceptors are formed, with association constants of 7.9 m 1 and 31.5 m 1, respectively, at 300 K in CDCl3. 

Complexes of MXs with dinitriles CN(CH2) CN ( = 1-4) have been prepared.Both [MXsL] and [MXsL ] have been isolated in the case of malonitrile, succinonitrile and glutaronitrile, whereas only [(MXs)2L] formed with adiponitrile. In the case of succinonitrile and glutaronitrile, trans conformers have been assigned to the 2 1 adducts, while a gauche conformation was assumed in 1 1 complexes the more stable gauche-trans-gauche conformation for adiponitrile was proposed in its 1 2 adducts. 

Synthesis of air and thermaUy stable Au(l) and Au(np alkoxy complexes AuORpL and Me2AuORpL (L=PR3) is readUy accomplished by m thesis between KORp and tiie coires ndmg halide in THF (equation 4) (21,22). The Au(I) complexes are found to be highly nucleophiUc, abstracting protons smoothly fiom malonitrile, methylcyanoacetate and even acetone to form the correqxmding C-bonded AuOD violate and HORp. The volatiUty of these complexes is not mmitioned. (Table VI)... 

Catalytic asymmetric Michael addition is an important reaction for creating carbon-carbon bonds with enantioselectivity. This reaction can be combined with other catalytic transformations to build up complex organic structures. A successful example is the enantioselective cascade Michael addition/H -hydrogenation catalyzed by ruthenium hydride borohydride complexes containing P-aminophosphine ligands 26 (Scheme 5.13) [19]. This approach has been extended to pentenones, heptenones, and nitrostyrene Michael acceptors and malonitrile Michael donors. 

Another example for the addition of two nucleophiles to 1,4-dimethoxycyclo-hexadienyliumiron complex salts is the sequential introduction of an aryl group and a malonitrile. In the first step, the aryllithium reagent adds to the 1-position of the 1,4-di-methoxycyclohexadienylium)iron complex salt (Scheme 4-172). Subsequent elimination of water or methanol under various conditions gives rise to l-aryl-4-methoxy-cyclohexadienyliumiron complexes. 

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