Tert-butyl isonitrile

In contrast to silylcarbenes, the analogous stannylcarbenes 2p are not stable, which explains why they have attracted little interest. Their instability is probably due to the long carbon-tin bond, which does not allow sufficient steric protection of the carbene center. Their reactivity seems to be quite similar to that of stable (phosphino)(silyl)carbenes Cyclopropanation reactions have been reported with methyl acrylate as well as coupling reactions with tert-butyl isonitrile.73... 

Zeeh, B., Mueller, E. Lewis acid-catalyzed reaction of aliphatic ketones and tert-butyl isonitrile. Liebigs Ann. Chem. 1968, 715, 47-51. 

The isocyanide-substituted complexes can be correspondingly obtained following thermal decarbonylation of the bromotetracarbonyl species with tert-butyl isonitrile to produce the cationic aminocarbyne complex [Cr(=CN Pr2)(CO)(CN Bu)4]. Subsequent treatment with Na[Cp] or K[Tp ] in tetrahydrofuran at 50 °C results in formation of LCr(=CN Pr2)(CO)(CN Bu) (L = Cp or Tp in 61 and 58% yield, respectively). In both reactions the minor product [Cr(=CN Pr2)(CN Bu)5] is formed by a competitive carbonyl-substitution reaction of the tetra(isonitrile) complex with liberated CN Bu. ... 

Yields higher than about 70% for any of these isonitrile preparations generally indicate incomplete fractionation. The purity of the product may be conveniently checked by proton magnetic resonance spectroscopy. The characteristic 1 1 1 triplet for tert-butyl isocyanide appears at <5 1.45 (chloroform-d). A small upheld peak usually indicates the presence of unreacted amine. Other common contaminants are dichloromethane and chloroform The purity may be determined more accurately by gas chromatographic analysis on a 230 cm. by 0.6 cm. column packed with 10%SE30 on Chromosorb G, 60-80 mesh, at 80°. 

Fig. 31. A comparison of the 1H chemical shifts for the E11 valine 72-CH3 protons of the various isonitrile complexes of isolated a chains (o) and p chains (A) of Hb A, the o ( ) and p ( ) chains as identified within an intact Hb A molecule, and sperm whale myoglobin ( ). Ligands CO, carbon monoxide M, methyl isocyanide E, ethyl isocyanide P, n-propyl isocyanide B, n-butyl isocyanide iP, isopropyl isocyanide and tB, tert-butyl isocyanide. [From Mims et al. (1983a)].

However, this behavior is not completely general, since fragmentation of likewise substituted imidoyls 5 can follow two competitive pathways depending on the stability of the released radical (R or Y). For instance, addition of methylsulfanyl radicals to tcrt-butyl isonitrile does not afford tert-butyl isothiocyanate (6, R = tert-Bu, X = S) but instead methyl thiocyanate (7, XY = SMe), due to preferential formation of the more stable tert-huiyl radical [5f]. 

The neuroexcitatory amino acid a-kainic acid, a popular testing ground for new pyrrolidine syntheses, has been prepared by a number of routes that involve free-radical cyclization reactions. Bachi has reported two approaches that involve iminoyl radical cyclizations. One enantioselective route is described in Scheme 6 [35]. Isonitrile 48 was prepared in 4 steps from 4-bromo-3-methyl-2-butenal dimethyl acetal, the key reaction being an enantioselective addition of tert-butyl oc-isocyanoacetate to an aldehyde mediated by Hiyashi s catalyst. Treatment of 48 with a catalytic... 

The use of phosgene in the presence of triethylamine has become an often applied method since Ugi s extensive works in this field [1157]. As a prelude to preparative isonitrile chemistry, Ugi s 1971 procedure for the production of tert-butyl isocyanide is presented [1165]. tert-Butyl formamide is dehydrated with phosgene to afford fert-butyl isocyanide in 82% yield. 

S. K. Guchait, C. Madaan, Org. Biomol. Chem. 2010, 8, 3631-3634. Towards molecular diversity dealkylation of tert-butyl amine in Ugi-type multicomponent reaction product establishes fcrt-butyl isocyanide as a useful convertible isonitrile. 

Berg FJ, Petersen JL (1991) Evidence of an alternative mechanism for the reductive coupling of isonitriles by electrophilic l-Sila-3-Zirconacyclobutane complexes. Structural characterization of the bicyclic enediamido complexes Cp2Zr(N(CMe3)C(CH2SiMe2CH2) =CN(R)) where R = tert-Butyl and 2,6-Xylyl. Organometallics 10 1599-1607... 

This method can he used for a variety of alkenes. The siliranes can he efficiently applied for thermal di-terf-butylsilylene transfer reactions to form other di-terf-hutylsiliranes (8), other thermal and photochemical ring expansion reactions, eg, to diastereoselectively form seven- (6,11), eight- (7), or nine-memhered heterocycles (12). Furthermore the siliranes may he applied to synthesize y-lactones (13), selective synthesis of tiiols, and homoallylic alcohols (14) or stereoselective formation of chiral allylic silanes (15) have also been reported. The following experimental procedure of isonitrile insertions exemplifies the silirane s high reactivity and facile formation of 1,1-di-terf-butyl-iminosilacyclobutanes (1,1-di-tert-butyl-iminosiletans or silacyclobutanimines) (4,5). 

Guchhait and Madaan (2010) reported a novel microwave-assisted one-pot novel tandem de-tert-butylation of tert-butyl amine in an Ugi-type multicomponent reaction product. Tert-butyl isocyanide has been explored as a useful convertible isonitrile for the first time affording access to molecular diversity of pharmaceutically important polycyclic N-fused imidazo-heterocycles. 

Acetylene passed slowly at 85° into a soln. of tert-buiy isocyanide and Ni-acetate in 1,2-didilorethane until spectroscopy shows disappearance of the startg. isonitrile after ca. 10 hrs. -> 5-t rr-butylamino-l-t rt-butyl-2-cyanopyrrole. Y 77%. F. e. and catalysts s. M. Jautelat and K. Ley, Synthesis 1970, 593. 

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