Formyl cyanide

The photooxidation of acrylonitrile by hydroxyl radicals in the presence of nitric oxide has been observed to yield formaldehyde (HCHO) and formyl cyanide (HCOCN) (Hashimoto et al. 1984). 

Thioformyl and thiocarbonyl cyanides. The long-sought for IR spectrum of this compound was obtained by Wentrup and coworkers162. S=CH—CN was prepared by Flash Vacuum Pyrolysis (FVP) of allyl cyanomethyl sulfide and condensed in an argon matrix. The absorption frequencies(in cm-1) and the intensities (in km mol-1) corresponding to the five bands observed were V2, CN stretch (2221, 17) vj, CH rock (1320, 11) U4, CS stretch (1103, 10) 05, CC stretch (889, 8) vg, CH wag (824, 26). These assignments were made on the basis of MP2/6-31G(d) calculations. The spectrum of formyl cyanide is reported and discussed elsewhere163. 

Substituted thiolactams (65) are obtained from lactams (63) in SS-100% yield by alkylation with Meerwein reagent and subsequent thiolysis of the resulting imidium salt (64 equation 29). The ap-proach has been extended to other thiolactams and acyclic examples employing a cyanohydrin derivative (66 equation 30). Similarly, A, N-acetals of formyl cyanide, (R2N)2CHC N, yield thioformamides on treatment with HaS. ... 

Masked formyl cyanides such as cyanohydrin alkyl ethers of formyl cyanide are also applicable to the aldol reaction. Palladium complexes, especially Pd2(dba)3-CHCl3, show high catalytic activities for the additions to aldehydes (Eq. 66) [136]. 

Nitrile See Formyl cyanide in The Combined Chemical Dictionary. 

Jung N, Brase S (2012) Vinyl and alkynyl azides well-known intermediates in the focus of modern synthetic methods. Angew Chem Int Ed 51(49) 12169-12171 Banert K, Potsing JR, Hagedom M, Reisenauer HP, Maier G (2008) Photolysis of open-chain 1,2-diazidoalkenes generation of 2-azido-2//-azirines, formyl cyanide, and formyl isocyanide. Tetrahedron 64(24) 5645-5648... 

In the presence of strongly acidic media, such as triflic acid, hydrogen cyanide or trimethylsilyl cyanide formylates aromatics such as ben2ene. Diprotonotated nittiles were proposed as the active electrophilic species in these reactions (119). 

The preparation of a formyl-substituted aromatic derivative 3 from an aromatic substrate 1 by reaction with hydrogen cyanide and gaseous hydrogen chloride in the presence of a catalyst is called the Gattermann synthesis This reaction can be viewed as a special variant of the Friedel-Crafts acylation reaction. 

The electrophile 4 adds to the aromatic ring to give a cationic intermediate 5. Loss of a proton from 5 and concomitant rearomatization completes the substitution step. Subsequent hydrolysis of the iminium species 2 yields the formylated aromatic product 3. Instead of the highly toxic hydrogen cyanide, zinc cyanide can be used. The hydrogen cyanide is then generated in situ upon reaction with the hydrogen chloride. The zinc chloride, which is thereby formed, then acts as Lewis acid catalyst. 

Synthesis of the remaining half of the molecule starts with the formation of the monomethyl ether (9) from orcinol (8). The carbon atom that is to serve as the bridge is introduced as an aldehyde by formylation with zinc cyanide and hydrochloric acid (10). The phenol is then protected as the acetate. Successive oxidation and treatment with thionyl chloride affords the protected acid chloride (11). Acylation of the free phenol group in 7 by means of 11 affords the ester, 12. The ester is then rearranged by an ortho-Fries reaction (catalyzed by either titanium... 

Formylation with Zinc Cyanide and HCI The Gatterman Reaction... 

Carbon monoxide, hydrogen cyanide, and nitriles also react with aromatic compounds in the presence of strong acids or Friedel-Crafts catalysts to introduce formyl or acyl substituents. The active electrophiles are believed to be dications resulting from diprotonation of CO, HCN, or the nitrile.64 The general outlines of the mechanisms of these reactions are given below. 

The latter is illustrated by the preparation of the previously unknown tetraformylselenophene by Morel (Eq. 26).88 The formyl group has also been introduced by treating dibromoselenophenes with copper cyanide in quinoline and reduction of the dicyano derivative obtained.89... 

The initiating nucleophile in the vast majority of these studies is the hydroxide anion. However, in principle, any nucleophile can add to the keto or formyl group to give rise to an anionic intermediate, which then could act as an intramolecular nucleophile and effect hydrolysis of the ester. Their relative effectiveness will depend on two factors the relative extent of formation and the nucleophilicity of the adduct. The nucleophiles that have been investigated are hydroxide, cyanide, morpholine and piperazine. The only quantitative comparison available is that of hydroxide, morpholine and piperazine, which are effective in the order of ca. 102 10-3 1 (Bender et al., 1965 Dahlgren and Schell, 1967). For morpholine and piperazine this is as expected on the basis of their relative basicities. However, the expected order of increasing formation of the adducts would be cyanide > nitrogen bases > hydroxide (Hine, 1971). At this time, these results cannot be analysed further, but more work on the systems could enable the structural dependence and reactivity to be elucidated. 

Glycosyl cyanides have been thoroughly used as starting materials in the preparation of 1-formyl, and 1-cyano-glycals, mainly through base-induced elimination procedures (Scheme 10). 

Scheme 10 Synthetic routes to 1-formyl and 1-cyano glycals from glycosyl cyanides.

Oxidation of 3-formyl-6-methoxycarbazole (97) with manganese dioxide and potassium cyanide in methanol afforded methyl 6-methoxycarbazole-3-carboxylate (104). Regioselective bromination of 97 afforded the 5-bromocarbazole 1031. Cleavage of the methyl ether to 1032, followed by nickel-mediated prenylation, provided micromeline (100) (547) (Scheme 5.154). 

For carbon substitution, magnesium dialkyls (and biphenyl) and lithium alkyls are effective in the absence of metal halides. Conditions have also been found for cyanide substitution and for hydro-formylation. 

Methoxyoxazolidines (464) are useful for the asymmetric formylation of various nucleophiles including silyl enol ethers (92X6011), trimethylsilyl cyanide (93SL921), enamines (90TL4223), and allyl silanes. 

Although the reaction of sodium cyanide with 2,6-anhydro-o-glycero-L-manno-heptose (6) (Scheme 2), a C-formyl galactopyranoside, seemed to occur with high level of... 

In contrast to the reactivity of the nitroethylenes, acrylonitrile generally reacts with indoles to form the l-(2-cyanoethyl) derivatives (B-70MI30500,79MI30501), whereas Michael addition at the 3-position requires the catalytic effect of copper(II) salts. The addition-elimination reaction of pyrroles and indoles with l,l-dicyano-2-ethoxyethylene proceeds in low yield (<30%) to give the dicyanovinyl derivatives, which can be converted by standard procedures into the formyl compounds (81H(16)1499). Tetracyanoethylene forms charge transfer complexes with indoles, which collapse to the Michael adduct anions and subsequently eliminate a cyanide ion with the formation of the tricyanovinylindole (B-70MI30500). 

The apparent fickleness of the acyl-pyrroles and -indoles in their reaction with carbanions to form new C—C bonds arises from the contribution made by the zwitterionic structure, e.g. (410b), to the resonance hybrid and the choice of the reaction conditions is critical for a successful nucleophilic reaction. Thus, formyl-pyrroles and -indoles do not normally undergo the Cannizzaro reaction nor do they form stable cyanohydrins or undergo benzoin-type reactions. However, surprisingly, 2-formylpyrrole reacts with arylaldehydes in the presence of potassium cyanide to yield (428), which is easily oxidized to (429) (B-77MI30505). It is noteworthy that the presence of an ester substituent adjacent to the formyl group modifies the mesomeric interaction to such an extent to allow the formation of (430) in low yield, as a result of an initial benzoin-type self-condensation (Scheme 76) (68BSF637). 

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