1 -Methyl-1 -phenyl-2- cyclopentane

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

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... 

Actually, 64 is known to be dimeric in the solid state but monomeric in dilute solution or in the gas phase. The first monomeric dialkyl- and diarylstannylenes are 2-pyridylbis[(tri-methylsilyl)methyl]-substituted stannylenes and bis[2,4,6-tris(tiifluoromethyl)phenyl]stan-nylene it should be stressed, however, that the coordination number around Sn in the solid state is not 2 in these compounds. The first actual monomer with coordination number 2 in the solid state was found to be 2,2,5,5-tetrakis(trimethylsilyl)cyclopentane-l-stannylene, 65, prepared by the following reaction141 ... 

Cathodic reduction of 1,3-diphenyl-propenone leads to l-hydroxy-2-benzoyl-3,4-diphenyl cyclopentanes with exclusive cis configuration of the two phenyl groups. With l-phenyl-l-pentene-3-one the cyclodimer 2-methyl-3,5-diphenyl-4-(l-propionyl)-cyclohexanone is formed with a 100% yield in an intramolecular Michael addition via an electrogenerated base. The substituents are all in the most stable equatorial position [277]. 

On the basis of these parameters we determined two possible transition states, 22 and 23. In transition state 22, the rhodium carbene is pointed away from the flip of the incipient cyclopentane ring (a chair-like transition state, counting the five carbons and the rhodium in the six-membered ring), whereas in 23 the rhodium carbene is pointed toward the flip of the incipient cyclopentane ring (a boat-hke transition state). As 10 (see Scheme 16.3) cyclizes to 12, in which the methyl and the phenyl are on the same face of the cyclopentane, we concluded that at the point of commitment to product formation, the transition state leading to cyclization must be chair-like 22 rather than boat-like 23. 

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... 

Vinyltins were used for synthetic purposes in radical addition-elimination sequences. The main limitation comes from the necessity to functionalize the olefin by groups such as esters able to stabilize the transient carbon-centred radical573. Phenyl-substituted systems proved to be reactive as well, whereas methyl- and cyclohexenyl-substituted ones failed to react574. An intramolecular version was developed giving access to methylene cyclopentane units (equation 44)575. 

Although methyl 2-siloxycyclopropanecarboxylates are cleaved by certain electrophiles, only tetracyanoethylene (TCNE) as a carbon electrophile could directly be added to phenyl or vinyl activated cyclopropanes providing cyclopentane derivatives 61). 

Benzoxazol 2-(l,l-Dimethy]-2-propenyl)- E8a, 1150 [Cl -> C(CH3)2-CH=CH2] lH-Carbazol 4a-Hydroxy-2,3,4,4a-tetrahydro- IV/lc, 483 Cyclobutan 1-Benzyl-l-cyan-3-hydroxy- E17e, 67 [(2-CN-ethyl) — oxiran + R —MgX] Cyclopentan-(spiro-2)-2,3-dihydro-indol - -3-oxo- VII/2a, 1051 Cyclopropan 2-Cyan-l-methoxy-2-methyl-l-phenyl- E17a, 764 (RO — CAr = Cr + En)... 

Methyl-3-[N-(l-phenyl-ethyl)-hydroxyamino]- -methylester E16a, 127 (R-NH-OH + En) Pyridin 3-(Dimethoxy-methyl)-4-(fnmy-3-hydroxy-cyclopentyl)-E7b/2, 483 C-[CH(OR)2]-1,2,4-triazin + 3-OH —1-(CO — CH3) — cyclopentan Pyridin-l-oxid 4-Ethoxy-2-(l-hydroxy-cyclohexyl)- E19d. 605 (H - Li/ -(- Keton) Pymolo l,2-a azepin 6-Ethenyl-5-methoxycarbonyl-3-oxo-(5R, 6S, 9aR )-octa-hy dro-E21b, 1974 l-[CH(OH) —... 

Als Metallierungsreagenzien konnen Butyl-, Phenyl-lithium, Lithium-diisopropylamid (LDA) oder -bis-[trimethylsilyl]-amid verwendet werden. Einige Beispiele zeigt Tab. 60 (S. 365). Bei Verwendung von 1,4-Dijod-pentan als Alkylierungsmittel tritt Cyclisierung zu 2-Carboxy-l-methyl-cyclopentan (70%) ein429. 

Photocyclisation of the 2,3-unsaturated a-C-glycoside having a 3-oxo-2-methyl-but-l-yl aglycon afforded the mixed isomers 79 to offer a new way of making functionalized cyclopentanes. In related work, 5e-phenyl 2-allylamino-... 

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