共查询到20条相似文献,搜索用时 15 毫秒
1.
Tsutomu Kimura Junichiro Nishida Gaku Kashiwamura Gen Kobayashi Tsuyoshi Satoh 《Tetrahedron letters》2014
A novel method for the synthesis of cyclopropane-fused α-chloro-γ-lactones was developed utilizing the nucleophilicity of cyclopropylmagnesium carbenoids. Cyclopropylmagnesium carbenoids were generated from i-PrMgCl and 1-chlorocyclopropyl p-tolyl sulfoxides with a [(phenoxycarbonyl)oxy]methyl group at the 2-position of the cyclopropane ring. The resulting cyclopropylmagnesium carbenoids reacted with an intramolecular carbonate unit to give 1-chloro-3-oxabicyclo[3.1.0]hexan-2-ones in moderate to good yields. The asymmetric synthesis of 1-chloro-3-oxabicyclo[3.1.0]hexan-2-one was achieved using optically active dichloromethyl p-tolyl sulfoxide as a starting material. 相似文献
2.
A. N. Kasatkin A. N. Kulak R. Kh. Biktimirov G. A. Tolstikov O. V. Shitikova V. R. Sultanmuratova 《Russian Chemical Bulletin》1992,41(4):740-747
2-Alkenylidenemalonic ester monoepoxides react with organolithium and organomagnesium compounds to give 1-ethoxycarbonyl-4-alkyl-6-alkenyl(alkyl, aryl, alkynyl)-3-oxabicyclo[3.1.0]hexan-2-ones in high yields. The latter, when an alkenyl fragment is present, undergo rearrangement in the presence of LiI to substituted 1-ethoxycarbonyl-3-oxabicyclo[3.3.0]-6-octen-2-ones or 3-(1,3-butadienyl)-4-butanolides.Institute of Chemistry, Bashkir Science Center, Ural Branch, Russian Academy of Sciences, Ufa 450054. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 4, pp. 946–954, April, 1992. 相似文献
3.
Pinto N Retailleau P Voituriez A Marinetti A 《Chemical communications (Cambridge, England)》2011,47(3):1015-1017
Phosphine catalyzed enantioselective [3+2] cyclizations on 4-substituted 2,6-diarylidenecyclohexanones and 2,4-diarylidene-bicyclo[3.1.0]hexan-3-ones take place with high diastereo- and enantioselectivity levels. The process affords spirocyclic compounds with excellent stereochemical control of up to five stereogenic centres. 相似文献
4.
[reaction: see text] A sequential acylation-intramolecular cyclopropanation reaction takes place upon treatment of a series of tetraalkylammonium acylchromates with beta,gamma-unsaturated acyl chlorides at -10 degrees C. The reaction leads to 2-oxabicyclo[3.1.0]hexan-3-ones with exo selectivity in good yields. The diastereoselectivity of the reaction allows the preparation of cis-divinyl cyclopropanes, which evolve via Cope sigmatropic reaction toward cycloheptadiene derivatives. Furthermore, the aromatic Cope rearrangement of a series of cis-aryl vinyl cyclopropanes prepared by means of this methodology has been studied. 相似文献
5.
Sebastian J. Welsch Michael UmkehrerGünther Ross Jürgen KolbChristoph Burdack Ludger A. Wessjohann 《Tetrahedron letters》2011,52(47):6295-6297
A variety of 1,6-enynes were synthesized by an Ugi-reaction and further elaborated by a PdII/IV catalyzed oxidative cyclization to produce N-substituted 3-aza-bicyclo[3.1.0]hexan-2-ones. Different substitution patterns were tested to examine the scope and limitations of the amide tethered substrates. 相似文献
6.
Hodgson DM Chung YK Nuzzo I Freixas G Kulikiewicz KK Cleator E Paris JM 《Journal of the American Chemical Society》2007,129(14):4456-4462
Lithium 2,2,6,6-tetramethylpiperidide (LTMP)-induced intramolecular cyclopropanation of unsaturated terminal epoxides provides an efficient and completely stereoselective entry to bicyclo[3.1.0]hexan-2-ols and bicyclo[4.1.0]heptan-2-ols. Further elaboration of C-5 and C-6 stannyl-substituted bicyclo[3.1.0]hexan-2-ols via Sn-Li exchange/electrophile trapping or Stille coupling generates a range of substituted bicyclic cyclopropanes. An alternative straightforward cyclopropanation protocol using a catalytic amount of 2,2,6,6-tetramethylpiperidine (TMP) allows for a convenient (1 g-7.5 kg) synthesis of bicyclo[3.1.0]hexan-2-ol and other bicyclic adducts. The synthetic utility of this chemistry has been demonstrated in a concise asymmetric synthesis of (+)-beta-cuparenone. The related unsaturated chlorohydrins also undergo intramolecular cyclopropanation via in situ epoxide formation. 相似文献
7.
Xu X Lu H Ruppel JV Cui X Lopez de Mesa S Wojtas L Zhang XP 《Journal of the American Chemical Society》2011,133(39):15292-15295
3,5-Di(t)Bu-QingPhyrin, a new D(2)-symmetric chiral porphyrin derived from a chiral cyclopropanecarboxamide containing two contiguous stereocenters, has been developed using an iterative approach based on Co(II)-catalyzed asymmetric cyclopropanation of alkenes. The Co(II) complex of 3,5-Di(t)Bu-QingPhyrin, [Co(P2)], has proved to be a general and effective catalyst for asymmetric intramolecular cyclopropanation of various allylic diazoacetates (especially including those with α-acceptor substituents) in high yields with excellent stereoselectivities. The [Co(P2)]-based intramolecular metalloradical cyclopropanation provides convenient access to densely functionalized 3-oxabicyclo[3.1.0]hexan-2-one derivatives bearing three contiguous quaternary and tertiary chiral centers with high enantiomeric purity. 相似文献
8.
The one-pot synthesis of benzo[f]quinolin-3-ones and benzo[a]phenanthridein-5-ones was achieved by the inter- and intramolecular photoannulation of 6-chloropyridin-2-ones and 3-chloroisoquinolin-1-ones with phenylacetylene or tethered phenylacetylene. The reactions were proceeded by photoaddition of 6-chloropyridin-2-ones and 3-chloroisoquinolin-1-ones to phenylacetylene to give the chlorine-substituted stilbenoids, and then 6π electrocyclization of the stilbenoids and oxidation aromatization to afford the polycyclic products. 相似文献
9.
Jie-You Xue Shi-Xiong Tang Ai-Bin Sun Fan Wu Li-Xin Qiao Yu-Rong Cao Xiao-Lan Wang 《中国化学》1992,10(5):445-450
Cyclopropanedicarboxylic acid anhydride can be converted to 4-substituted 3-oxabicyclo-[3.1.0]hexan-2-one by reaction with Grignard reagents in ether or tetrahydrofuran solution. 相似文献
10.
Greggory M. Wells Travis Dudding Lee Belding Jeffery A. Frick Abhijit Nayek Junfeng Huang Steven J. Katz Stephen C. Bergmeier 《Tetrahedron》2012,68(21):3980-3987
The reaction of fused ring aziridines, 3-oxa-1-azabicyclo[3.1.0]hexan-2-ones, with amine nucleophiles can provide either an aminomethyl oxazolidinone or an aziridinyl urea. The amine, reaction solvent, and aziridine substitution have been examined with the aid of computational studies to identify reaction conditions that provide a single product. Polar solvents provided only the aminomethyl oxazolidinone products. Formation of aziridinyl ureas required control of aziridine substitution, solvent, and reactant stoichiometry. 相似文献
11.
Irradiation of 8-oxabicyclo[3.2.1]oct-6-en-2-ones results in a 1,3-acyl rearrangement. The initial photoproduct undergoes a subsequent reaction involving hydrogen transfer followed by intramolecular cycloaddition of a ketene intermediate. 相似文献
12.
Optically pure sulfinylfuranones undergo oxidation at sulfur followed by a totally stereoselective epoxidation at the electron deficient double bond by treatment with MCPBA at room temperature to afford, in good yields, enantiomerically pure 4-ethoxy-5-alkyl-1-p-tolylsulfonyl-3,6-dioxabicyclo[3.1.0]hexan-2-ones. These epoxyfuranones are obtained along with cyclopropanefuranones by reaction of 4-ethoxy-6-p-tolylsulfinylfuro[3,4-c]pyrazolin-6-ones with MPCBA. In both cases, the formation of the sulfonyl epoxylactones takes place by oxidation of the sulfonylfuran-2(5H)-one resulting from the starting materials. This reaction is completely stereoselective (controlled by the configuration of C-5 of furanone) and results from the nucleophilic attack of the peroxycarboxylate generated by interaction of the reagent with weak basic centres at the substrates. 相似文献
13.
Intramolecular [2+2] cycloaddition of γ,δ-unsaturated ketenes derived from hex-5-enoyl chloride derivatives gave bicyclo[2.1.1]hexan-5-ones with complete regioselectivity. 相似文献
14.
Tsuyoshi Satoh Takahiro Tsuru Shotaro Ikeda Toshifumi Miyagawa Hitoshi Momochi Tsutomu Kimura 《Tetrahedron》2012,68(4):1071-1084
The addition reactions of α,β-unsaturated carbonyl compounds with dichloromethyl p-tolyl sulfoxide in the presence of NaHMDS or LDA resulted in the formation of adducts, 1-chlorocyclopropyl p-tolyl sulfoxides bearing a carbonyl group at the 2-position, in almost quantitative yields. The carbonyl group of the adducts was transformed to various ether groups to give 1-chlorocyclopropyl p-tolyl sulfoxides bearing an ether functional group at the 2-position in short steps. Treatment of these products with i-PrMgCl at low temperature afforded cyclopropylmagnesium carbenoids via the sulfoxide-magnesium exchange reaction. 1,5-Carbon–hydrogen insertion (1,5-CH insertion) reaction of the generated magnesium carbenoid intermediates took place to give 3-oxabicyclo[3.1.0]hexanes or bicyclo[3.1.0]hexanes bearing an ether group at the 4-position in moderate to good yields. When this procedure was carried out starting with enantiopure dichloromethyl p-tolyl sulfoxide, enantiopure 3-oxabicyclo[3.1.0]hexanes were obtained in good overall yields. These procedures provide a good way for the synthesis, including asymmetric synthesis, of multisubstituted 3-oxabicyclo[3.1.0]hexanes and bicyclo[3.1.0]hexanes from α,β-unsaturated carbonyl compounds and dichloromethyl p-tolyl sulfoxide in short steps. 相似文献
15.
New 3-oxy substituted and 3,6-dioxydisubstituted 7-oxabicyclo[2.2.1]heptan-2-ones have been prepared. The regioselectivity of their Baeyer-Villiger oxidation has been determined and compared with that of other 7-oxabicyclo[2.2.1]heptan-2-one derivatives. If the substituent at C(3-exo) is an O-acyl or another group less electron-releasing, the bridgehead C(1) migration is favoured, leading to 2,8-dioxabicyclo[3.2.1]octan-3-ones. When the substituent at C(3) is a MeO or (tBu)Me2SiO group, the Baeyer-Villiger oxidation leads to 3,8-dioxabicyclo[3.2.1]octan-2-ones due to preferred C(3) migration. The latter regioselectivity is higher for 3-endo-MeO than for 3-exo-MeO substituted ketones and it can be enhanced by remote oxy substituents at the C(6-endo) position. 相似文献
16.
Hitherto unknown nucleoside analogues incorporating the five naturally occurring nucleic acid bases built on a 2-oxabicyclo[3.1.0]hexane template were synthesized. The synthesis of these new conformationally restricted nucleoside analogues involved the preparation of a suitable sugar precursor bearing the 2-oxabicyclo[3.1.0]hexane scaffold. This sugar was readily obtained from [(3aS,6aS)-2,2-dimethyl-3a,6a-dihydrofuro[2,3-d][1,3]dioxol-5-yl]methyl benzyl ether (4) following a Simons-Smith-type cyclopropanation reaction. Finally, glycosylation reactions and deprotection provided the nucleoside analogues. Using nucleoside 14 bearing thymine base as a model, we found that the conformation of such nucleoside analogue was restricted toward a (0)T(1) conformation. 相似文献
17.
Tetsuro Shimo Hidemi Minamishin Kenichi Somekawa 《Journal of heterocyclic chemistry》1997,34(2):533-536
Dehydrochlorination of chlorinated 5-hydroxy-2-oxabicyclo[3.2.0]heptan-4-ones, 3a-c, which were obtained from the photo[2+2]cycloadditions between 4-hydroxy-3(2H)-furanone 1 and chloroethylenes, with triethylamine gave 2-ethenyl-3(2H)-furanones 4a,b or 2-(2-cyanoethyl)-3(2H)-furanone 4c. 2-Oxa-bicyclo[3.2.0]hept-6-en-4-ones 7 being [2+2]cycloadducts between 1 and acetylenes gave 2,3-dihydro-3-oxooxepin derivatives 8 by electrocyclic rearrangement. 相似文献
18.
Niklas Radhoff Dr. Constantin G. Daniliuc Prof. Dr. Armido Studer 《Angewandte Chemie (International ed. in English)》2023,62(34):e202304771
Design, synthesis and application of benzene bioisosteres have attracted a lot of attention in the past 20 years. Recently, bicyclo[2.1.1]hexanes have emerged as highly attractive bioisosteres for ortho- and meta-substituted benzenes. Herein we report a mild, scalable and transition-metal-free protocol for the construction of highly substituted bicyclo[2.1.1]hexan-2-ones through Lewis acid catalyzed (3+2)-cycloaddition of bicyclo[1.1.0]-butane ketones with disubstituted ketenes. The reaction shows high functional group tolerance as documented by the successful preparation of various 3-alkyl-3-aryl as well as 3,3-bisalkyl bicyclo[2.1.1]hexan-2-ones (26 examples, up to 89 % yield). Postfunctionalization of the exocyclic ketone moiety is also demonstrated. 相似文献
19.
The title compounds 1a and 1b have been synthesized in two steps from the saturated pyran-3-ones 2a and 2b , respectively. Upon irradiation (254 nm or 350 nm) in dilute solutions (10?3?10?2M ), compounds 1 undergo a formal [4 + 2] cycloreversion from the excited triplet state to give (2-methylprop-1-enyl)ketene ( 11 ) and either formaldehyde or acetone, ketene 11 being trapped by H2O or MeOH to afford 4-methylpent-3-enoic acid ( 5 ) or its methyl ester 4 in 75–85% isolated yield. In this (monomolecular) photoreaction, heterocycles 1 differ from their alicyclic counterparts, i.e., 4,4-dimethylcyclohex-2-enone ( 10a ) and 4,4,6,6-tetramethylcyclohex-2-enone ( 10b ), as no rearrangement to a 4-oxabicyclo[3.1.0]hexan-2-one occurs. On the other hand, the photochemical behavior of pyranone 1a in bimolecular reactions (cyclodimerization, [2 + 2] cycloaddition to 2,3-dimethylbut-2-ene) resembles that of enone 10a . 相似文献
20.
Vapor phase pyrolysis of 2,4-pentadienaldehyde, of 6-oxabicyclo[3.1.0]hex-2-ene or of 3-pentenoic acid chloride at 600° (0.1 s/1 Torr) leads to similar mixtures containing the stereoisomers of 2, 4-pentadienaldehyde and 1-propenylketene. These compounds, and methyl substituted derivatives thereof, equilibrate at 600° (0.1 s) through intramolecular processes involving cis/trans-isomerisations and [1,5]-H-shifts. It is shown that α, β-γ, δ-unsaturated aldehydes can be prepared in high yield through gas phase thermolysis of appropriately substituted acid chlorides. 相似文献