Of cyclopropane carbonitril

NHase from Rhodococcus. sp. AJ270 was isolated, purified, and applied to the enantiose-lective transformation of a series of cyclopropane carbonitriles. Amides with moderate ee were isolated from conversion of many of the cyclopropane substrates, to yield the amides trans-( IR, 2/ )-3-phenylcyclopropane carbonitrile (49% conv. 22.7% ee), trans-( IS, 35)-2,2-dimethyl-3-phenylcyclopropanecarbonitrile (40% conv. 84.7% ee), trans-( IR, 3/f)-2,2-dibromo-3-phenylcy-clopropanecarbonitrile (11.6% conv. 83.8% ee), cis-( IR, 25)-3-phenylcyclopropanecarbonitrile (25.8% conv. 95.4% ee), and cis-(lR, 2S )-2,2-dimethyl-3-phenylcyclopropanecarbonitrile (7.9% conv. 3.2% ee) [43],... 

The thermolysis (- 10 to -t- 25°C) or photolysis (2 > 300 nm, - 10°C) of 3//-diazirine-3-car-bonitriles generates cyanocarbenes under very mild reaction conditions (see Houben-Weyl, Vol. E19b, pl206). Their addition to electron-rich alkenes yielded cyclopropane carbonitriles in moderate yields (Table 3). The 3//-diazirines-3-carbonitriles were prepared from 3-halodiazirines, mostly in situ, by an exchange reaction with tetrabutylammonium cyanide. The cyclopropanation of (Z)- or ( )-but-2-ene proceeded nonstereospecifically, which is explained by the participation of a triplet carbene. 

The copper salt mediated synthesis of 1-alkoxycarbonylcyclopropane-l-carbonitriles from cy-anoacetates and alkenes or l,l-dichloro-4-methylpenta-1,3-diene is described in Section 1.2.1.2.4.2.9. An analogous synthesis of cyclopropane-1,1-dicarbonitriles has been claimed. Instead of l,l-dichloro-4-methylpenta-l,3-diene, 3,4-dibromo-l,l-dichloro-4-methylpent-l-ene can be utilized to form 1 (no yield given). ... 

When one hydrogen atom is replaced by a functional group, four isomers are formed in the process of the structural isomerization. Calculations [47] and experimental study [48,49] were performed on cyclopropane carbonitrile (C3H5CN), where the functional group is a -C = N group. 

FIGURE 6.4 Comparison between the calculated [47] and experimental [48,49] rate constants of the cyclopropane carbonitrile isomerizations. 

The isomerization of cyclopropane carboxaldehyde to propenyl aldehyde involves an opening of the cyclopropane ring and H-atom shift to form a methyl group. The pathway for this process is very similar to the one that has been found for cyclopropane carbonitrile that has been described in Section 6.2.2. 

U V irradiation of readily available oxirane-2-carbonitriles with at least one aromatic substituent attached to the three-membered ring results in a facile photofragmentation to cyanocarbenes and carbonyl compounds (see Houben-Weyl, Vol. E19b, pll98). In the presence of alkenes, cyclopropane-l-carbonitriles are formed (Table 1). This method is especially useful for the synthesis of 1-phenylcyclopropane-l-carbonitriles in moderate to good yields. ... 

Photochemical, thermal, and transition metal catalyzed decomposition of diazoacetonitrile in the presence of an alkene yields cyclopropanecarbonitriles by transfer of cyanocarbene (see Houben-Weyl, Vol. E19b, pl202). If the UV irradiation was carried out in (Z)-but-2-ene as solvent, cw-2,3-dimethylcyclopropane-l-carbonitrile (c -l) was formed as the major product cisjtrans 94 6). The percentage of the franj-product can be decreased by the addition of a radical scavenger, such as 1,2-diphenylethene, whereas it can be increased by dilution with dichloromethane. By carrying out the decomposition of diazoacetonitrile as a gas-phase thermolysis, fm i -2,3-dimethylcyclopropane-l-carbonitrile (irans-l) becomes the major product of the cyclopropanation cisltrans 38 62). ... 

Alkenylcyclopropane-l -carbonitriles were obtained in moderate to good yields, in some cases even with good diastereoselectivity, by the photolysis of 3/f-pyrazole-5-carbonitriles in unsaturated solvents (Table 4). On UV irradiation, the pyrazoles isomerize to jS,> -unsaturated a-diazocarbonitriles, which cannot be isolated but decompose rapidly to l-alkenyl(cyano)car-benes, which then either cyclize to cyclopropenecarbonitriles 1 or react with the alkene substrate to give 1 -alkenylcyclopropane-1 -carbonitriles 2. As a rule, the cyclopropanation of electron-rich alkenes, dienes, thiophene, and furan dominates the intramolecular carbene reaction. A generalized procedure can be found in Houben-Weyl, Vol. 19b, p 1209. 

By analogy to a synthesis of 1,1-dialkoxycarbonylcyclopropanes and 1-ethoxycarbonylcyclo-propane-l-carbonitriles from alkenes and malonic esters or cyanoacetic esters, respectively (see Section 1.2.1.2.4.2.9.), cyclopropane-1,1-dicarbonitriles were obtained from 1,3-dienes and malonodinitrile in the presence of iodine and solid potassium carbonate under phase-transfer conditions. ... 

Benzyloxy(cyano)carbene would be expected to be electrophilic by virtue of the calculated selectivity index, Wp -HjOccN 111- This has not yet been experimentally proved as 3-bcnzyloxy-3-cyano-3//-diazirine is rather labile and cannot be isolated if it is synthesized by the substitution of chlorine by a cyano group in 3-benzyloxy-3-chloro-3if-diazirine consequently, this substitution reaction is carried out in the presence of an alkene, hence, preparing 1-benzyloxy-cyclopropane-l-carbonitrile derivatives. However, the cyanide ion present in the system induces the polymerization of electrophilic alkenes, such as acrylonitrile or methyl acrylate. 

On heating, a 4 1 mixture of acrylonitrile and (chloromethylene)cyclopropane gave a 5 4 mixture of Irons- and cK-4-chlorospiro[2.3]hexane-5-carbonitrile (11). This product was formed regioselectively, hence a stepwise mechanism involving a diradical was assumed. 

Two types of reactivity of bicyclobutanes with electron-deficient alkenes and alkynes have been known for many years ". These are an ene-like reaction and a cycloadditionlike reaction. The first is typified by the room-temperature addition of dicyanoacetylene (200) to 3-methylbicyclobutane-l-carbonitrile (224) to furnish 225 as the major product and the second by the reaction between 224 and acrylonitrile at elevated temperature to give the bicyclo[2.1.1]hexane 226 ". More recently a third mode of reaction has been describedfor which the prototype is addition of tricyclo[3.1.1.0 ]heptane ( Moore s hydrocarbon , 227) to tetracyanoethylene (228) to form cyclopropane 229 It is noteworthy that 227 is incapable of undergoing either the ene-type reaction, which would produce an olefin violating Bredt s Rule, or the... 

R. erythropolis (previously R. rhodochrous) AJ270, which has been utilized in many enantioselective transformations of nitriles such as cyclopropane, oxirane, and aziridine analogs [10, 12], was recently proved to catalyze the enantioselective hydrolysis of azetidine-2-carbonitriles [13] and P-lactam carbonitriles also [14] (Figure 11.2). Carboxylic acids and carboxamides were also obtained with significant enantiomeric excesses from 3-hydroxy-4-aryloxybutanenitriles and 3-hydroxy-3-arylpropanenitriles (Figure 11.3) using R. rhodochrous ATCC BAA-870 [15], which is more elaborately discussed in Chapter 14. 

R. erythropolis AJ270 Cyclopropane, oxirane, aziridine carbonitriles Enantiopure trans- and cis-cyclopropanecarboxylic acids and carboxamides, oxirane and aziridine carboxamides Chemoenzymatic synthesis of various building blocks [100-104]... 

---