Insertion reactions nitrile

Intermediate arylamidine, 6S, is prepared by the aluminum chloride-catalyzed addition of aniline to the nitrile function of 4-cyanothiazole (67), Amidine, 65, is then converted to its N-chloro analog (69) by means of sodium hypochlorite. On base treatment, this apparently undergoes a nitrene insertion reaction to produce thiabendazole (70), ... 

To date most of the nitriles studied have been simple alkyl or aromatic derivatives with little other functionality. We recently attempted to extend the reaction to iV-protected a-aminonitriles, derived by dehydration of a-aminoacid amides (Path A, Scheme 25), but this proved unsatisfactory, and therefore we investigated an alternative diazocarbonyl based route in which the order of steps was reversed, i.e. a rhodium catalysed N-H insertion reaction on the amide followed by cyclodehydration to the oxazole (Path B, Scheme 25). 

Since alkyllithium compounds and their carbanions have an isoelectronic structure with alkoxides, their reaction behavior with carbenes is expected to be similar to that of alkoxides, showing enhanced reactivity in both C-H insertion and hydride abstraction.35 In this reaction, the hydride abstraction cannot be followed by recombination and, therefore, can be differentiated from the insertion. Indeed, the reaction of alkyllithium compounds 70 or nitrile anions (see Section IV.B) with ethyl(phenylthio)carbenoid, which is generated by the reaction of 1-chloropropyl sulfide 69 with BuLi, takes place at the -position of 70 more or less in a similar manner giving both insertion product 71 and hydride abstraction products 72 and 73, respectively. This again supports a general rule C-H bonds at the vicinal position of a negatively charged atom are activated toward carbene insertion reactions (Scheme 22). 

Photolysis of nitrile oxide 377 (R = CNO) gives acylnitrene 377 (R = CON), which undergoes intramolecular insertion reactions to give products 378 and 379 (428). 

Zirconium and hafnium dialkylamides are highly reactive compounds. They undergo (i) protolytic substitution reactions with reagents such as alcohols, cyclopentadiene and bisftrimethylsilyOamine 63 64 (ii) insertion reactions with C02, CS2, COS, nitriles, phenyl isocyanate, methyl isothiocyanate, carbodiimides and dimethyl acetylenedicarboxylate 69-72 and (iii) addition reactions with metal carbonyls.73 These reactions are summarized with reference to Zr(NMe2)4 in Scheme 1. 

Several of the reactions described in Section 6.16.2.4.6.1 are two-step reactions. After the initial [2+1] addition of the silylene to the multiple bond, a second insertion reaction of a silylene into a reactive Si-X bond of the cyclopropane derivative takes place yielding four-membered ring compounds. Examples are the reactions with alkynes, nitriles, imines, and ketones. 

Copper salts were found to be successful catalysts for the insertion of nitriles into silacyclopropenes (Scheme 7.28).99,100 A screen of different copper salts identified (CuOTf)2-PhMe as the optimal catalyst. This reaction occurs readily at room temperature for monosubstituted silacyclopropenes to afford azasilacyclopentadienes... 

Organocopper compounds react slowly with nitriles or not at all 124, 233). Only a low yield of benzanilide was obtained from the reaction between phenylcopper and phenyl isocyanate 124). Isocyanate insertion reactions with vinylcopper compounds in HMPT in the presence of P(0C2H5)3 afford acrylamides 225a). 

Insertion Reactions of Nitriles, Thiocyanates, Carbodi-imides and Other Nitrogen-Containing Compounds... 

The entrance into the catalytic cycle from complex 5 may occur via a small equilibrium concentration of Ni-(la)-(MVN) complex6 (pathA, Schemes) and/or via oxidative addition of HCN to generate the species Ni-[la]-HCN, 7 (pathB). In either event, formation of the hydridoalkene complex Ni-[1]-(MVN)(H)(CN), 8, occurs and is followed by an insertion reaction to produce the (ri -benzyl)nickel cyanide intermediate 9. Although this allyl-type species has not been directly detected, the exclusive formation of the branched nitrile supports its intermediacy. Analogous intermediates have been postulated in the hydrocyanation of 1,3-butadiene with NilPlO-o-tolylljjj or Ni[P(OEt)3]4 and in the hydrocyanation of styrene with Ni[P(0-p-tolyl)3]4. Examples of other nick-el-benzyl complexes exhibiting similar allylic interactions in the solution and solid state are also known. 

Hydroacylation of Michael acceptors. The organotetracarbonylferrates obtained by alkylation of disodium tetracarbonylferrate undergo insertion reactions with Michael-type acceptors to give eventually y-keto esters, ketones, and nitriles. The last example shows an interesting synthesis of a cyclopentanone by an intramolecular insertion reaction. ... 

The migration (insertion) reaction may also occur in the case of many other unsaturated molecules such as SO2, CO2, N2, NO, nitriles, isonitriles, and ketones. The insertion of sulfur dioxide may proceed very rapidly. The NMR and IR measurements show that the reaction proceeds through O-sulfinates which subsequently undergo rearrangement to give stable S-sulfinates ... 

The acid cleavage of simple [RCo(CN)5] derivatives is complex because cyano ligands on a metal ion are also susceptible to protonation. The protonated CN becomes an isonitrile-type ligand and undergoes an insertion reaction with the alkyl ligand to give, ultimately, a nitrile or a carboxylic acid 114,116). 

SCHEME 12.43 a-bonds insertion reactions with nitriles. 

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