- Photochemical Decomposition of Benzocyclobutenone p-Toluenesulfonylhydrazone
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The photochemical decomposition of benzocyclobutenone p-toluenesulfonylhydrazone led to a wide variety of products including the E- and Z-isomers of 1,1'-bi(benzocyclobutenylidene) 6a; cis-trans-benzocyclobutenylidene trimer 7; cyclohepatrienes 8-10; benzocyclobutenone azine in it's anti-anti(11), anti-syn (12), and syn-syn conformations (13); anti- and syn-benzocyclobutenone N-benzocyclobutenyl-N-tosylhydrazone (14 and 15, respectively); (benzocyclobutenyl)hydrazine (16); benzocyclobutenyl p-tolyl sulfone (17); and benzocyclobutenone 1.Their isolation, identification and mechanism of formation are discussed.The data indicate that while the addition of arylcarbenes to alkenes results in the preferential formation of the more-hindered syn products, arylcarbene 5 adds to aryl olefins (styrenes and dimer 6) in a stereospecific anti orientation to give the less-hindered product.In addition, the minimal steric effects observed in these systems presumably results from the 90 deg angle of the cyclobutyl ring, which pulls the phenyl ring back and thus minimizes its steric contribution.
- Frimer, Aryeh,Weiss, Joseph,Rosental, Zilpa
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- A very short synthesis of steroids from 1,3-butadiene and benzocyclobutenes
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Lewis acid mediated addition of 1,8-bis(trimethylsilyl)octa-2,6-diene (BISTRO) 1 to succinic anhydride led to spirolactone 2 [(±)-6,9-divinyl-1-oxaspiro[4.4]nonan-2-one]. Methoxycarbonylation followed by stereoselective alkylation by various benzocyclobutenes afforded the substituted benzocyclobutene steroid precursors 5. Thermolysis of 5 gave rise to steroids (±)-6 with a transanti-cis configuration in five steps and in a highly stereoselective manner. Modifications of the sequence allowed the preparation of steroids (±)-11 with trans-anti-trans configuration.
- Michellys,Maurin,Toupet,Pellissier,Santelli
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- Catalytic Asymmetric Homologation of Ketones with α-Alkyl α-Diazo Esters
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The homologation of ketones with diazo compounds is a useful strategy to synthesize one-carbon chain-extended acyclic ketones or ring-expanded cyclic ketones. However, the asymmetric homologation of acyclic ketones with α-diazo esters remains a challenge due to the lower reactivity and complicated selectivity. Herein, we report the enantioselective catalytic homologation of acetophenone and related derivatives with α-alkyl α-diazo esters utilizing a chiral scandium(III) N,N′-dioxide as the Lewis acid catalyst. This reaction supplies a highly chemo-, regio-, and enantioselective pathway for the synthesis of optically active β-keto esters with an all-carbon quaternary center through highly selective alkyl-group migration of the ketones. Moreover, the ring expansion of cyclic ketones was accomplished under slightly modified conditions, affording a series of enantioenriched cyclic β-keto esters. Density functional theory calculations have been carried out to elucidate the reaction pathway and possible working models that can explain the observed regio- and enantioselectivity.
- Tan, Fei,Pu, Maoping,He, Jun,Li, Jinzhao,Yang, Jian,Dong, Shunxi,Liu, Xiaohua,Wu, Yun-Dong,Feng, Xiaoming
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supporting information
p. 2394 - 2402
(2021/02/16)
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- Synthetic approach to benzocyclobutenones using visible light and a phosphonate auxiliary
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Reported herein is a two-step procedure to synthesize benzocyclobutenones from (o-alkylbenzoyl)phosphonates. It consists of a visible-light-driven cyclization reaction forming phosphonate-substituted benzocyclobutenols and subsequent elimination reaction of the H-phosphonate, which assumes a key role as the recyclable auxiliary. A wide variety of functionalized benzocyclobutenones, which include those difficult to synthesize by conventional methods, are efficiently synthesized.
- Yano, Takaaki,Kawasaki, Tairin,Yuhki, Tatsuya,Ishida, Naoki,Murakami, Masahiro
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supporting information
p. 1224 - 1227
(2018/02/23)
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- 1-Aminobenzocyclobutene-1-phosphonic Acid and Related Compounds as Inhibitors of Phenylalanine Ammonia-Lyase
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Five new geminal aminocycloalkanephosphonic acids (4 – 8) containing both an aromatic ring and a cycloalkane ring were synthesized and evaluated as potential inhibitors of buckwheat phenylalanine ammonia-lyase (PAL). Within the set of compounds which are related to 2-aminoindane-2-phosphonic acid (AIP, 3), a known powerful inhibitor of PAL, racemic 1-aminobenzocyclobutene-1-phosphonic acid (4), was six times weaker than AIP as an in vitro inhibitor of buckwheat PAL, but six times stronger than AIP as an in vivo inhibitor of phenylalanine-derived anthocyanin synthesis in buckwheat.
- Zoń, Jerzy,Miziak, Piotr
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- Synthesis of a polymerizable benzocyclobutene that undergoes ring-opening isomerization at reduced temperature
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1-Ethoxyvinylbenzocyclobutene is a substituted benzocyclobutene that undergoes radical polymerization to produce polymers that can be crosslinked at 100-150 °C. The 4- and 5-vinyl isomers are synthesized in a 1:4 ratio via a halogenated benzyne intermediate produced from anthranilic acid, followed by cycloaddition with ethyl vinyl ether and replacement of the halogen atom with a vinyl group. Georg Thieme Verlag Stuttgart · New York.
- Pugh, Coleen,Baker, James S.,Storms, William K.
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supporting information
p. 148 - 152
(2014/01/06)
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- Design and synthesis of conformationally constrained analogues of cis-cinnamic acid and evaluation of their plant growth inhibitory activity
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1-O-cis-Cinnamoyl-β-d-glucopyranose is known to be one of the most potent allelochemical candidates and was isolated from Spiraea thunbergii Sieb by Hiradate et al. (2004), who suggested that it derived its strong inhibitory activity from cis-cinnamic acid, which is crucial for phytotoxicity. In this study, key structural features and substituent effects of cis-cinnamic acid (cis-CA) on lettuce root growth inhibition was investigated. These structure-activity relationship studies indicated the importance of the spatial relationship of the aromatic ring and carboxylic acid moieties. In this context, conformationally constrained cis-CA analogues, in which the aromatic ring and cis-olefin were connected by a carbon bridge, were designed, synthesized, and evaluated as plant growth inhibitors. The results of the present study demonstrated that the inhibitory activities of the five-membered and six-membered bridged compounds were enhanced, up to 0.27 μM, and were ten times higher than cis-CA, while the potency of the other compounds was reduced.
- Nishikawa, Keisuke,Fukuda, Hiroshi,Abe, Masato,Nakanishi, Kazunari,Tazawa, Yuta,Yamaguchi, Chihiro,Hiradate, Syuntaro,Fujii, Yoshiharu,Okuda, Katsuhiro,Shindo, Mitsuru
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p. 223 - 234
(2014/01/06)
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- Enzymatic Baeyer-Villiger oxidation of Benzo-Fused ketones: Formation of regiocomplementary lactones
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Baeyer-Villiger monooxygenases (BVMOs) are enzymes that are known to catalyse the Baeyer-Villiger oxidation of ketones in aqueous media using O2 as oxidant. Herein, we describe the oxidation of a set of diverse benzo-fused ketones by three different BVMOs
- Rioz-Martinez, Ana,De Gonzalo,Torres Pazmino, Daniel E.,Fraaije, Marco W.,Gotor, Vicente
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experimental part
p. 2526 - 2532
(2009/09/25)
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- DENDRITIC MOLECULAR INTRACELLULAR TRANSPORTERS AND METHODS OF MAKING AND USING SAME
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In accordance with the purpose(s) of the invention, as embodied and broadly described herein, the invention, in one aspect, relates to compounds comprising the structure: and at least one guanidinium residue, wherein m is zero or a positive integer. Also disclosed are methods of preparing the disclosed compounds. Also disclosed are methods of intracellular delivery comprising administering the disclosed compounds and compositions to a subject. Also disclosed are pharmaceutical compositions comprising a therapeutically effective amount of one or more compounds or compositions of the invention and a pharmaceutically acceptable carrier. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.
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Page/Page column 104
(2010/11/30)
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- The elusive benzocyclobutenylidene: A combined computational and experimental attempt
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Ab initio and density functional theory calculations predict that benzocyclobutenylidene (1) has a singlet ground state in contrast to the parent phenylcarbene and many other simply substituted arylcarbenes. Calculations also predict that 1 should lie in a relatively deep potential well, while its triplet state is 14.5 kcal mol-1 higher in energy. However, attempts to observe 1 directly by photolysis of two different nitrogenous precursors were not successful. Irradiation of diazobenzocyclobutene (7) (λ > 534 nm or λ > 300 nm) or azibenzocyclobutene (10) (λ > 328 nm) in Ar matrixes at 10 K leads to the formation of the strained cycloalkyne 7-methylenecyclohepta-3,5-dien-1-yne (3). 13C-Labeled 3 was also prepared in a similar manner. There is very good agreement between experimental IR spectra and computationally derived harmonic vibrational frequencies for 3 and [13C]-3 and excellent agreement between observed and calculated isotopic shifts. Prolonged short-wavelength irradiation converts 3 into benzocyclobutadiene (5). Phenylacetylene (6) and benzocyclobutadiene dimer (11) were identified as products arising from flash vacuum pyrolysis of diazirine 10 at 500 °C.
- Nicolaides,Matsushita,Yonezawa,Sawai,Tomioka,Stracener,Hodges,McMahon
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p. 2870 - 2876
(2007/10/03)
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- Improved synthesis of benzocyclobutenone by flash vacuum pyrolysis
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Flash vacuum pyrolysis of o-toluoyl chloride at 780 °C under 0.5 mmHg afforded benzocyclobutenone in higher yield (80%) than previously reported one (28 %).
- Suzzarini, Laurence,Lin, Jian,Wang, Zhi Yuan
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p. 1695 - 1696
(2007/10/03)
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- Toluene dioxygenase-catalysed oxidation route to angular cis-monohydrodiols and other bioproducts from bacterial metabolism of 1,2-dihydrobenzocyclobutene and derivatives
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A mutant strain (UV4) of the soil bacterium Pseudomonas putida, containing toluene dioxygenase, has been used in the metabolic oxidation of 1,2-dihydrobenzocyclobutene 12? and the related substrates 1,2-dihydrobenzocyclobuten-1-ol 13 and biphenylene 33. Stable angular cis-monohydrodiol metabolites (1R,2S)-bicyclo[4.2.0]octa-3,5-diene-1,2-diol 7, (1S,2S,8S)-bicyclo[4.2.0]octa-3,5-diene-1,2,8-triol 8 and biphenylene-cis-1,8b-diol 9, isolated from each of these substrates, have been structurally and stereochemically assigned. The structure, enantiopurity and absolute configuration of the other cis-diol metabolites, (2R,3S)-bicyclo[4.2.0]octa-1(6),4-diene-2,3-diol 14 and cis-1,2-dihydroxy-1,2-dihydrobenzocyclobutene 16, and the benzylic oxidation bioproducts, 1,2-dihydrobenzocyclobuten-1-ol 13, 1,2-dihydrobenzocyclobuten-1-one 15 and 2-hydroxy-1,2-dihydrobenzocyclobuten-1-one 17, obtained from 1,2-dihydrobenzocyclobutene and 1,2-dihydrobenzocyclobuten-1-ol, have been determined with the aid of chiral stationary-phase HPLC, NMR and CD spectroscopy, and stereochemical correlation. X-Ray crystallographic methods have been used in the determination of absolute configuration of the di-camphanates 27 (from diol 7) and 32 (from diol 9), and the di-MTPA ester 29 (from diol 14) of the corresponding cis-diol metabolites. The metabolic sequence involved in the formation of bioproducts derived from 1,2-dihydrobenzocyclobutene 12 has been investigated.
- Boyd, Derek R.,Sharma, Narain D.,Evans, Timothy A.,Groocock, Melanie,Malone, John F.,Stevenson, Paul J.,Dalton, Howard
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p. 1879 - 1886
(2007/10/03)
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- A study of the vacuum pyrolysis of 4-diazo-3-isochromanone with HeI ultraviolet photoelectron spectroscopy
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A newly developed ultraviolet photoelectron spectrometer -CO2 laser instrument that utilizes a 50-W CW laser as a directed heat source was used to study the vacuum pyrolysis of 4-diazo-3-isochromanone (1).Analysis of the pyrolysate with ultraviolet photoelectron spectroscopy and photoionization mass spectrometry established that 1 undergoes a facile, unexpected pyrolysis at a laser power level of 26 W yielding N2, CO, and benzocyclobutenone (6).A multistep mechanism beginning with the formation of 4-carbena-3-isochromanone (2), which rearranges to oxaketene 3, can be written for the reaction.If 3 is an intermediate, it must be unusually thermally labile for it readily decarbonylates to 2-carbena-3,4-benzotetrahydrofuran (4).The ring opening of 4 into the ortho-quininoid ketene 5 and the cyclization of 5 into 6 are possible final steps in the conversion of 1 into 6. - Key words: vacuum pyrolysis; 4-diazo-3-isochromanone; HeI ultraviolet photoelectron spectroscopy.
- Werstiuk, N. H.,Ma, J.,Roy, C. D.,Kresge, A. J.,Jefferson, E.
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p. 1738 - 1740
(2007/10/02)
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- Photosensitized Oxidation of 1,1'-bi(benzocyclobutenylidene)
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In an attempt to explore whether singlet molecular oxygen reactions could be used to obtain access antiaromatic species, we carried out the Rose Bengal photosensitized oxygenation of (E)- and (Z)-1,1'-bi(benzocyclobutenylidene) (7-E and 7-Z).The photooxygenation resulted in a facile E/Z isomerization accompanied by the sluggish uptake of oxygen and formation of benzocyclobutenone 8, spiroindanone 9, phthalide 10, and dione 11.We found no evidence, however, for the generation of the corresponding benzocyclobutadiene via a 1O2-ene reaction.On the contrary, the data suggests that the isomerization of the diaryl olefin can occur in the absence of sensitizer, while product formation is a free radical autoxidative process, presumably initiated by the interaction of excited dye with molecular oxygen (''type IIc'').The formation of 8-11 may be rationalized in terms of secondary rearrangements (unzipping and cyclization) of the initially formed polyperoxide or polyperoxy radical.The absence of singlet oxygen ene product may reflect the increased activation energy required to generate an antiaromatic product.Alternatively, the inability of the ring methylene hydrogens to attain a pseudoaxial conformation may actually be the controlling factor in inhibiting the ene process.
- Frimer, Aryeh, A.,Weiss, Joseph
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p. 3660 - 3667
(2007/10/02)
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- Organometallic Derivatives of Cyclopropanes
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The tricarbonylchromium complex of cyclopropanaphthalene (3a) is deprotonated at C(1) with BuLi.Quenching of the resulting anion with MeI results in a 1:1 mixture of stereoisomeric methyl derivatives 6a and 6b.Peterson olefination of the bis-silylated complex 3b affords the complexed alkylidenecycloproparene 5 in low yield.The tricarbonylchromium complex of cyclopropaanthracene (10) is accessible via bis-hydro-desilylation of 9.Its X-ray structure is also reported.All attempts to synthesize a tricarbonylchromium complex of benzocyclopropene (11a) failed.
- Mueller, Paul,Bernardinelli, Gerald,Jacquier, Yvan
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p. 1995 - 2008
(2007/10/02)
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- A novel synthesis of benzocyclobutenones
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Lithium-iodine exchange initiated cyclization of o-iodo-N-methoxy-N-methyl phenylacetamides provides a simple and efficient route to benzocyclobutenones.
- Singh Aidhen,Ahuja
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p. 5431 - 5432
(2007/10/02)
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- Preparation of Benzocyclobutenones via the Photochemical Cyclization of 1-(ortho-Alkylary)-2,2,4-trimethylpentane-1,3-diones
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Irradiation of 1-(ortho-methylaryl)- and 1-(ortho-ethylaryl)-2,2,4-trimethylpentane-1,3-diones 4a-g in hexane gave benzocyclobutenols 10a-g.However, irradiation of 1-(ortho-isopropylaryl)-2,2,4-trimethylpentane-1,3-diones 4i and 4j resulted in no reaction.Irradiation of 1-mesityl-2,2,4-trimethylpentane-1,3-dione 4h gave a complex mixture of products.Pyrolysis of benzocyclobutenols 10a, b, d-f gave benzocyclobutenones 11a, b, d-f and 2,4-dimethylpentan-3-one 2, whereas that of the benzocyclobutenols 10c, g gave the starting 1,3-diketones 4c, g predominantly along with small amounts of benzocyclobutenones 11c, g and the dimethylpentanone 2.
- Yoshioka, Michikazu,Momose, Shinobu,Nishizawa, Kaori,Hasegawa, Tadashi
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p. 499 - 503
(2007/10/02)
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- Photochemical Reaction of 1-(o-Methylphenyl)-2,2-dimethyl 1,3-Diketones
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The photochemistry of 1-(o-methylphenyl)-2,2-dimethylpropane-1,3-diones 4 has been investigated.Compounds 4a-h underwent photocyclization to give benzocyclobutenols 11a-h and naphthalenones 12a-h in hexane or methanol.Compound 4i gave the naphthalenone 12i in methanol.The product ratio 11:12 was greater in hexane than in methanol.This ratio increases with chain branching of the C-3 substituent R and with increasing size of R.Compounds 4a, b and d gave isobutyrophenones 13a, b and d along with products 11 and 12 in hexane.
- Yoshioka, Michikazu,Nishizawa, Kaori,Arai, Masayuki,Hasegawa, Tadashi
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p. 541 - 547
(2007/10/02)
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- Bacterial oxidation of benzocyloalkenes to yield monol, diol and triol metabolites
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Benzylic monooxygenation of benzocycloalkenes, 2-4, by enzymes in intact cultures of Pseudomonas putida UV4 yielded exclusively the [R] enantiomers, 6-8, and the derived ketones 10-12; by contrast, biotransformation of benzocyclobutene, 1, yielded both monooxygenation (5 and 9), dioxygenation (13,14 and 15), and trioxygenation (16) products.
- Boyd, Derek R.,Sharma, Narain D.,Stevenson, Paul J.,Chima, Jagdeep,Gray, David J.,Dalton, Howard
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p. 3887 - 3890
(2007/10/02)
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- Photochemical Reaction of o-Alkylphenyl 1,3-Diketones. A New Method for the Preparation of Benzocyclobutenones
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Irradiation of o-alkylphenyl 1,3-diketones (1) in hexane gave benzocyclobutenols (2) which underwent thermal retro-aldol cleavage to yield benzocyclobutenones (3).
- Yoshioka, Michikazu,Arai, Masayuki,Nishizawa, Kaori,Hasegawa, Tadashi
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p. 374 - 375
(2007/10/02)
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- FLASH PYROLYSIS OF 4-METHYLENE-1,2,3,-BENZOTRIAZINES
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Flash vacuum pyrolysis of 3-alkyl-4-methylene-1,2,3-bentzotriazines gives products derived from benzocyclobutane N-alkylimines and to a lesser extent from 2-methylene-benzazetidines.Benzocyclobutane N-phenylimine is formed in high yield by flash pyrolytic elimination of HCl from N-phenyl-2-methyl benzimidoyl chloride.
- Noyce, S. J.,Randles, K. R.,Storr, R. C.
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p. 941 - 944
(2007/10/02)
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- NEW GENERATION AND CYCLOADDITION OF α-(N-TERT-BUTYLIMINO)-o-QUINODIMETHANE
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CsF induced 1,4-elimination of ammonium bromide, prepared by quaternization of N-tert-butyl o-(dimethylaminomethyl)benzimidoylsilane 6, provides a new generation of α-(N-tert-butylimino)-o-quinodimethane (3a), which gives benzocyclobutenone N-tert-butylimine (8) in the absence of dienophile.Trapping of 3a with electron deficient olefins affords Diels-Alder adducts regioselectively.
- Ito, Yoshihiko,Nakajo, Eiji,Saegusa, Takeo
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p. 5139 - 5142
(2007/10/02)
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- THERMAL ADDITION REACTIONS TO BENZOCYCLOBUTENONES STUDIED BY FLASH PHOTOLYSIS
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Ortho-quinoid vinylketenes 2 have been generated thruogh flash photolysis of benzocyclobutenones 1.A kinetic study of intermolecular addition reactions of 2 competing with the recyclization 2 -> 1 reveals strikingly different substituent effects for the addition of methanol and of dienophiles.
- Schiess, P.,Eberle, M.,Huys-Francotte, M.,Wirz, J.
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p. 2201 - 2204
(2007/10/02)
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- Benzocyclobutenes. Part 9. Synthesis of Bromo-, Chloro-, and Oxo-derivatives of Benzocyclobutene and Naphthocyclobutene
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Addition of benzyne to 1,1-dichloro- and 1,1,2-trichloro-ethene gave the corresponding di- (61percent) and tri- (18percent) chloro derivatives of benzo-cyclobutene.Similarly 2,3-didehydronaphthalene and 1,1-dichloroethene gave 1,1-dichloronaphthocyclobutene.Some reactions, including reduction, chlorination, bromination, and hydrolysis of these cyclobutenes and of related compounds are described.
- Abou-Teim, Omar,Goodland, Michael C.,McOmie, F. W.
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p. 2659 - 2662
(2007/10/02)
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- An Efficient and Remarkably Regioselective Synthesis of Benzocyclobutenones from Benzynes and 1,1-Dimethoxyethylene
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New efficient methodology for the synthesis of substituted benzocyclobutenones is presented that involves the cycloaddition of various substituted benzynes to 1,1-dimethoxyethylene followed by hydrolysis to the corresponding ketone.In most cases studied a high degree of regioselectivity was observed.These observations are consistent with a nonsynchronous mechanism wherein steric and inductive considerations can be used to account for the products observed.
- Stevens, Robert V.,Bisacchi, Gregory S.
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p. 2393 - 2396
(2007/10/02)
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- Practical Multigram Syntheses of Benzocyclobutenediones
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Experimentally simple syntheses of benzocyclobutenedione and substituted benzocyclobutenediones (3-OH; 4-OH; 4-Me; 3-OH, 5-Me) are described which allow the synthesis of these compounds on large scale from inexpensive starting materials.The regiospecific and stereoselective cycloaddition of trimethylsiloxy dienes to 1,4-dichloro-3,3,4-trifluorocyclobutene forms the basis of the synthesis of the substituted benzocyclobutenediones.
- South, Michael S.,Liebeskind, Lanny S.
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p. 3815 - 3821
(2007/10/02)
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- Synthesis and Chemistry of 2-Trimethylsilylbenzocyclobutenones
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Pyrolysis of o-trimethylsilylmethyl- and o-bis(trimethylsilyl)methyl-benzoyl chlorides affords 2-silylated benzocyclobutenones.
- Chenard, Bertrand L.,Slapak, Christopher,Anderson, D. Keith,Swenton, John S.
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p. 179 - 180
(2007/10/02)
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- Benzocyclobutenylidene-Cycloadditions, Reactivity, and Multiplicity
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EHT and CNDO/2 calculations on benzocyclobutenylidene (6) are described.Flash pyrolysis of the tosylhydrazone salt 7 affords benzocyclobutene and o-xylene in low yield, along with the formal syn and anti carbene dimers 13 and 14.Condensed-phase reactions were achieved by photolysis of the salt 15.Benzocyclobutenylidene (6) gave rise to the formal carbene dimers 17 and 18.Insertion of carbene 6 into the carbon-hydrogen bonds of 2,3-dimethylbutane produced the benzocyclobutenes 20 and 21 (insertion ratio tertiary:primary = 9:1).Cycloaddition of 6 to olefins gave only spirohexene derivatives 22.Multiplicity studies of 6 with cis or trans olefins indicated that 6 undergoes cycloaddition in a stereospecific manner.Competition experiments using dienes and monoolefins implicate an equilibrium between singlet and triplet 6.Further competition experiments with styrene/para-substituted styrene pairs demonstrated that 6 reacts faster with electron-poor styrenes.Possible explanations for this apparent anomaly are discussed.
- Duerr, Heinz,Nickels, Helmut,Pacala, Luba A.,Jones, Maitland
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p. 973 - 980
(2007/10/02)
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- The preparation and characterization of benzocyclobutenylidene-, naphtho[b]cyclobutenylidene-, and η2-benzocyclobutadiene-η5-cyclopentadienyldicarbonyliron hexafluorophosphate
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The preparation and characterization of the first isolable cationic mononuclear complexes bearing a η2-cyclobutadienoid ligand or a carbene ligand lacking heteroatom stabilization are described. The reaction between 1-bromo-benzocyclobutene and Na[η5-C5H5(CO)2Fe] (NaFp) afforded η1-1-benzocyclobutenyl-η5-cyclopentadienyldicarbonyliron (III). Treatment of III with trityl hexafluorophosphate gave benzocyclobutenylidene-η5-cyclopentadienyldicarbonyliron hexafluorophosphate (V). Naphtho [b] cyclobutenylidene-η5-cyclopentadienyldicarbonyliron hexafluorophosphate (VI) was formed in an analogous manner. Both V and VI gave 1,1-disubstituted cyclobutenes when treated with nucleophilic reagents. η2-Benzocyclobutadiene-η5-cyclopentadienyldicarbonyliron hexafluorophosphate, (XIX), which was prepared by the oxidation of bis-1,2-(η5-cyclopentadienyldicarbonyliron)benzocyclobutene by trityl hexafluorophosphate, afforded trans-1,2-disubstituted benzocyclobutenes when treated with nucleophilic reagents. The η2-benzocyclobutadiene ligand of XIX was displaced by I- and trapped as the Diels--Alder adduct by 1,3-diphenylisobenzofuran.
- Sanders, Andrea,Bauch, Thomas,Magatti, Charles V.,Lorenc, Carol,Giering, Warren P.
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p. 359 - 375
(2007/10/05)
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