Dicyclopropyl

Benzyl-cyclopropan 4-Methoxy-benzyl-cyclopropan 4-Chlor-benzyI-cyclopropan Dicyclopropyl-methan... 

Beim BenzoyI-cyclopropan(- 1,38 V) erhalt man dagegen neben 1-Oxo-l-phenyl-butan iiberwiegend infolge Dimerisierung 1,2-Dicyclopropyl- , 2-diphenyl-glykolb. 

Cyclopropylchlorocarbene [20] has been generated by UV photolysis (A = 335 nm) of cyclopropylchlorodiazirine [21] frozen in a nitrogen matrix at 12 K (Ho et al., 1989). IR and UV spectra of [20] have been recorded. The reaction of [20] with HCl resulted in the formation of (dichloromethyl)-cyclopropane [22], and annealing of the matrix gave (dicyclopropyl)dichloro-ethene [23]. Subsequent irradiation (A = 450 nm) of the carbene [20] led to its isomerization to 1-chlorocyclobutene [24], which was partialy destroyed to give ethene and chloroacetylene. Ab initio calculations predict the existence of two carbene conformers, but attempts to distinguish them in IR or UV spectra were unsuccessful. 

Similarly, the Pd-catalyzed arylation of l,3-dicyclopropyl-l,2-propadiene 6/1-122 with iodobenzene in the presence of dimethyl maleate led to the diastereomeric cyclopropane derivatives 6/1-124 and 6/1-125 via 6/1-123 in 86% yield as a 4 l-mix-ture [65] (Scheme 6/1.33). Several other aryl halides and dienophiles have been used in this reaction. 

An experimental and calculational NMR investigation of dicyclopropyl substituted cyclobutylmethyl cation (19)45 has shown that IGLO/DZ//B3LYP/6-31G(d) calculated 13C NMR chemical shifts facilitate the assignment of the spectra. 

Knoke and de Meijere [60] recently developed a highly flexible domino Heck-Diels-Alder reaction of a symmetrically substituted cumulene 125, which also involves cross-couplings of an allene at the central position. Both aryl and hetaryl halides react efficiently with l,3-dicyclopropyl-l,2-propadiene (125) and furnish 1,3,5-hexatriene derivatives 126 as intermediates, which are usually trapped by acceptor-substituted olefins in a subsequent cycloaddition, providing adducts 127a/b in moderate to good overall yields (Scheme 14.30). 

Conjugated dienes yield mono-adducts with dihalocarbenes at the more electron-rich C=C bond further reaction at the less reactive bond may also occur [e.g. 4,8,19, 23, 31, 37, 49, 62, 69, 94]. Cycloheptatriene yields the syn- and nnti-1,2 5,6-bis-adducts (14.5 and 22.9%) and the syn-1,2 5,6-ann -3,4-tris-adduct with dichloro-carbene [62], The facile reaction of cyclopropylethenes with dihalocarbenes produces dicyclopropyl compounds [53, 117]. Isoprene reacts with chloro(phenylthio)carbene across the more reactive 1,2-bond (51%) [146]. 

Neuerdings wurden durch WoLFF-KiSHNER-Reduktion cc./J-unge-sattigter Ketone die Cyclopropankohlenwasserstoffe 2-Phenyl-dicyclo-propyl (III) (228), l.l-Pentamethylen-bicyclo(0.1.4)heptan (IV) (114) some einige l-Phenyl-2-alkylcyclopropane (88) dargestellt. Versuche Cyclopropylvinylketon auf diesem Wege in Dicyclopropyl zu verwandeln fiihrten nicht zum Ziel (235). 

Reaction of Cyclopropylchlorid with Lithium. Isolation of Dicyclopropyl. 

Important improvement in the in vitro activity was obtained when the central proline was replaced by thiaproline (thiaPRO) to give compound 66, suggesting that modification of the central amino acid (of the proline type) could be of importance in modulating the PEP inhibitory activity, Eq. (25) [76]. In fact, replacement of the proline moiety of63 - 66 by non-natural amino acids derived from 2-perhydroindole or from 2-azabicyclo[2.2.2]octane and modulation of the side chain by replacement of the terminal phenyl ring by a dicyclopropyl-carbinyl moiety afforded derivatives such as 67 and 68 with improved activities (IC50 between 10 and 20 nM), Eq. (26). 

Several 1,4-disubstituted derivatives of the dication, 63, were successfully prepared. The 1,4-diphenyl, 1,4-dimethyl, 1,4-dicyclopropyl-substituted derivatives of carbodication 63 (65, 66, and 67) are exceptionally stable. The 1,4-dimethyl-1,4-cyclohexyl dication, devoid of the adjacent cyclopropyl groups, could not be prepared. The carbocationic center in all these dications are somewhat shielded as compared to their monocations. The C NMR chemical shifts of the carbocationic centers for the dications 65, 66, and 67 are 235.4, 293.4, and 260.8 ppm, respectively. The diprotonated ann -tricyclo(5.1.0.0 )octa-2,6-dione, 68, may be treated as a dicarboxonium ion, instead of dihydroxy dicarbenium ion, since the cabronyl carbon is shielded by only 25.2 ppm, much smaller than that observed for the protonated cyclohexanedione (34 ppm). The para carbons of the phenyl substituents in carbodication 65 are relatively shielded by about 5 ppm from that of the parent l,4-diphenylcyclohexane-l,4-diyl dication showing relatively less delocalization of the charge into the aromatic rings. 

Es stellte sich heraus, da6 Dicyclopropyl-keton ein brauchbarer Sensibilisator fiir die Dimerisierung von Norbomen zu den Dimeren (46) und (47) ist, da die Umsetzung bis zu 46% ohne Nebenproduktbildung ablauft (34). 

OH NaCBHj/NiClj-6H20/CH30H -30" 60 min Amino-dicyclopropyl- methan 70 6... 

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