Methylcyclopropane

Ethyl-methyl 1-Butene, (Z)- and (E)-butene, methylcyclopropane (E)-Butene, isobutene, methylcyclopropane... 

The photolysis of a-diazosulfones dissolved in alkenes provides sulfonyl-substituted cyclopropanes in high yields. This is exemplified by the preparation of l-(p-methoxyphenylsulfonyl)-2,2,3,3-tetra-methylcyclopropane in 75% yield from -methoxybenzenesulfonyl-diazomethane and 2,3-dimethyl-2-butene. A similar addition to [Pg.101]

The radical is generated by photolytic decomposition of di-/-butyl peroxide in methylcy-clopropane, a process that leads to selective abstraction of a methyl hydrogen from methylcyclopropane ... 

Methylcyclopropane shows strikingly different reactivity toward chlorination and bromination under radical-chain conditions. With chlorine, cyclopropyl chloride (56%) is the major product, along with small amounts of 1,3-dichlorobutane (7%). Bromine gives a quantitative yield of 1,3-dibromobutane. Offer an explanation for the difference. 

In strong base, propene reacts with chloroform to yield 2,2-dichloro-1 -methylcyclopropane. 

With a substitution pattern as found in l-vinyl-2-methylcyclopropane 7, a retro-ene reaction (see Ene reaction) may take place to yield hexa-1,4-diene 8 ... 

Because in metathesis reactions with most catalyst systems a selectivity of nearly 100% is found, a carbene mechanism seems less likely. Banks and Bailey ( ) reported the formation of small quantities of C3-C6-alkenes, cyclopropane, and methylcyclopropane when ethene was passed over Mo(CO)6-A1203, which suggests reactions involving carbene complexes. However, similar results have not been reported elsewhere most probably the products found by Banks and Bailey were formed by side reactions, typical for their particular catalyst system. 

Dalton H, BT Gording, BW Watyers, R Higgins, JA Taylor (1981) Oxidations of cyclopropane, methylcyclopropane, and arenes with the monooxygenase system from Methylococccus capsulatus. J Chem Soc Chem Commun 482-483. 

These results are inconsistent with a radical rebound mechanism because this mechanism is a two-step process that requires the involvement of intermediates. Instead the results suggest that the hydroxylation is a concerted process, much like a singlet carbene reaction, which does not involve intermediates. However, this conclusion is in conflict with the properties of singlet carbene reactions discussed above. Subsequent studies on a number of substituted methylcyclopropanes and other stained hydrocarbon systems established that these findings were not anomalous. 

FIGURE 4.6 Cytochrome P450-catalyzed oxidation of constrained methylcyclopropane 9. 

Azatricyclo[2.2.1.02 6]hept-7-yl perchlorate, 2368 f Azetidine, 1255 Benzvalene, 2289 Bicyclo[2.1.0]pent-2-ene, 1856 2-/ert-Butyl-3-phenyloxaziridine, 3406 3 -Chloro-1,3 -diphenyleyclopropene, 3679 l-Chloro-2,3-di(2-thienyl)cyclopropenium perchlorate, 3388 Cyanocyclopropane, 1463 f Cyclopropane, 1197 f Cyclopropyl methyl ether, 1608 2,3 5,6-Dibenzobicyclo[3.3.0]hexane, 3633 3,5 -Dibromo-7-bromomethy lene-7,7a-dihy dro-1,1 -dimethyl-1H-azirino[l,2-a]indole, 3474 2.2 -Di-tert-butyl-3.3 -bioxaziridinc, 3359 Dicyclopropyldiazomethane, 2824 l,4-Dihydrodicyclopropa[ >, g]naphthalene, 3452 iV-Dimethylethyl-3,3-dinitroazetidine, 2848 Dinitrogen pentaoxide, Strained ring heterocycles, 4748 f 1,2-Epoxybutane, 1609 f Ethyl cyclopropanecarboxylate, 2437 2,2 -(l,2-Ethylenebis)3-phenyloxaziridine, 3707 f Methylcyclopropane, 1581 f Methyl cyclopropanecarboxylate, 1917 f Oxetane, 1222... 

Although allyl alcohol yields a complex mixture of products [9], substituted allylic alcohols react with dihalocarbenes to form, almost exclusively, the hydroxy-methylcyclopropanes [10-13], which undergo acid-catalysed ring opening to produce cyclopentenones [9] (see Section 7.3). 

Pines, H., W. D. Huntsman and V. N. Ipatieff Isomerization Accompanying Alkylation. VII. Reaction of Benzene with Methylcyclopropane, Ethylcyclopropane and with Dimethylcyclopropanes. J. Amer. chem. Soc. 73, 4343 (1951). 

The Arrhenius equations for the various reactions are shown in Table 1. The geometrical isomerizations of 1,2,3-trimethylcyclopropane and l-ethyl-2-methylcyclopropane have also been studied. In both cases geometrical isomerization is faster than the structural isomerization reactions to yield olefins. The Arrhenius equations obtained were ... 

The kinetics of the thermal isomerization of methylcyclopropane to four isomeric butanes have been determined from rate-constant measurements over a wide range of temperatures 695-1154 K. The kinetic parameters are consistent with the formation... 

---