Cyclopropane, 1-acetyl-1 -phenyl

Cyclopentane, 1-cyano-l-phenyl-, 55, 94 Cyclopentane, methyl-, 55, 62, 112 Cyclopropane, 1-acetyl-1-phenyl-, 55, 94... 

PENTAMETHYL-, 56, 1 Cyctopentane, acetyl-, 55, 25 Cyclopentane, 1-cyano-l-phenyl-, 55, 94 Cyclopentane, methyl, 55, 62 Cyclopentanol p-toluenesulfonate, 55, 112 Cyclopentene, 56, 34, 58, 73 2-Cyclopenten-l-one, 2,5-dialkyl- 58, 62 CYCLOPENTENONES, 58, 56 Cyclopropane, 1 -acetyl-1 -phenyl-, 55, 94 Cyclopropane, 1, l-dibromo-2,2-diphenyl-, 56, 32... 

Cyclohexene-l,4-dione, 2,3,5-tiichloro-3, 6-bis(l,l-dimethylethyl)- [5-Cyclo-hexcne-1,4-dione, 2,3,5-tnchloio-3,6-dwert-butyl-], 55, 33 Cyclopentadiene, 55, 15,16 Cyclopentane acetyl-,55,25 Cyclopentane 1-cyano-l-phenyl-, 55,94 Cyclopentane methyl-, 55, 62 Cyclopropane, 1-acetyl-l-phenyl-, 55 94... 

Cyclopropanes. XIII. 1-Acetyl-2-nitro-3-phenyl-cyclopropane and its... 

Alkenylidene cyclopropanes react readily with 246 to yield 1,4-diazo-bicyclo[3,3,0]oxtanes, whereas methylidene cyclopropane reacts only very slowly with 246 to yield a 2 + 2 cycloadduct (73AJ1553). Compound 246 also reacts with 5-methylfuran-2(3//)-one in an acyl-ene reaction to yield 7-acetyl-6,7-dihydro-2-phenyl-2.ff-pyrazolo[I,2-a]-l,2,4,-triazol-l,3, 5-trione [80JCS(P1)843]. 

Thus the unsaturated ketones carvone, eucarvone and 1-acetyl-cyclohexane formed the cyclopropyl ketones (6), (7) and (8) while benzalaceto-phenone (9) affords l-benzyl-2-phenyl-cyclopropane as a mixture of cis and trans isomers (10) and (ll).233,234... 

Bennett and coworkers (138) have prepared the acetyl radical CH CO by the reaction between Na and acetyl chloride and have obtained an isotropic value of 5.1 gauss for the proton splitting. An ESR spectrum attributed to CH CO with 16 gauss was earlier reported during photolysis of biacetyl (276) in a solid matrix. Recently a series of benzoyl 6-radicals (277) have been observed in the liquid photolysis of the corresponding benzaldehyde in a cyclopropane solution containing di-t-butyl peroxide. For the first time, it is possible to study in these radicals the delocalization of the unpaired electron from the acyl 6-system into the adjacent phenyl ir-system. The significant conclusion from this study is the... 

The a proton of a substituted cyclopropane is also rendered acidic if the substituent is attached to the ring by C-P bonds. A few reports have appeared on a-substitution in such compounds.(Cyclopropyl)triphenylphosphonium bromide was converted to a (1-ethoxy-carbonylcyclopropyl)triphenylphosphonium salt 18 in 80% yield by sequential treatment with lithium diisopropylamide and ethyl chloroformate. Furthermore, some diethyl cyclopropyl-phosphonates were converted, in some cases in excellent yield, to diethyl (1-hydroxymethyl-cyclopropyl)phosphonates by treatment with lithium diisopropylamide followed by addition of an aldehyde." Thus, typically, diethyl 2-hexylcyclopropylphosphonate gave diethyl 2-hexyl-l-[hydroxy(phenyl)methyl] cyclopropylphosphonate (19b) in 90% yield on reaction with benzaldehyde. ° Other electrophiles such as acetone, acetyl chloride, acetic anhydride, and ethyl acetate, were not sufficiently reactive to undergo addition to the anion. 

When 1-acetyl-l-bromo-2-buty Icy cl opropane was heated in methanol in the presence of triphenylphosphane either of the acceptor-substituted cyclopropane bonds was cleaved and the halide was found at C2 or C3. In the case of the 2-phenyl derivative the solvent acted as the nucleophile and added across the most activated cyclopropane bond. Experimental evidence has shown that the reaction proceeds via an initial reductive debromination and a subsequent triphenylphosphane promoted opening of the ring by nucleophilic attack of bromide or alcohol. 

Epoxide 303 has been used an an enantioselective synthesis of the methylenecyclopropa-neacetic acid (514a) portion of (methylenecyclopropyl)acetyl-CoA (514b), a mammalian metabolite of hypoglycines A and B. Addition of the anion derived from phenyl 2-(tri-methylsilyl)ethyl sulfone to 303 produces a 3 1 mixture of threo and erythro diastereomers 509. Either diastereomer cyclizes to the same cyclopropane 511 upon treatment with LDA, which suggests that epimerization at C-5 must be occurring prior to cyclization. Selective removal of the TBPS group followed by oxidation of the alcohol to an acid and elimination affords the desired product 514a (Scheme 73) [126,127]. 

At temperatures above about 80°C, to decayed with first order kinetics (k = 1.7 x 10 sec at 100°C). At 120°C the spectrum due to to was replaced by that of the benzyl radical, At no temperature between 100 and 200°C was it possible to detect the spiro-octadienyl radical, kly (which may be only a transition state in the rearrangement rather than a discrete intermediate) or the phenylacetyl radical, UjR. However, Ug can be detected when it is generated at low temperatures (22). Photolysis of a cyclopropane solution of di-tert-butyl peroxide and phenyl-acetaldehyde at -ll6°C gave the E.S.R. spectra of i g and 5 simultaneously (id). At this temperature ks - 9 x 10 sec , while at 125°C, the temperature at which the original attempt was made to prepare 1,2-dibenzoylethane from acetophenone ( ), we can estimate that ks would be ca. 10 sec (id). It is clear that at 125°C, no bimolecular reaction of HR could be fast enough to compete with its decarbonylation. Hence, radical Ug cannot itself be directly involved in any of the reactions that lead to resinous materials in the acetophenone-acetyl peroxide reaction. 

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