Cyclopropane, 1-acetyl-l-phenyl

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... 

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

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

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. 

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... 

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]. 

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. 

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