7020-25-9Relevant academic research and scientific papers
One-pot synthesis of cyclopropane derivatives with a cis : Trans stereoselectivity by Wittig olefination-sulfur ylide cyclopropanation sequence
Huang, Wenhua,Wang, Lai-Ling
, p. 380 - 384 (2013/07/26)
Cyclopropane derivatives were synthesised in one pot from aromatic aldehydes, phenacyltriphenylphosphonium bromide, and S-phenacylthiolanium bromide by a Wittig olefination-sulfur ylide cyclopropanation sequence. When Cs2CO3 was used as the base and CH3CN/water (8:2, v/v) as the solvent, the major product was the cis-1,2-dibenzoyl cyclopropane. In contrast, when using DBU as the base and MeOH as the solvent, the major product was transdibenzoyl cyclopropane. In some cases, the major isomer was obtained in high purity and good yield by simple filtration.
Indium(I) bromide-promoted stereoselective preparation of cyclopropanes via sequential aldol-type coupling/elimination/Michael-induced ring closure reaction from α,α-dichloroacetophenone and aldehydes
Peppe, Clovis,das Chagas, Rafael Pav?o,Burrow, Robert Alan
, p. 3441 - 3445 (2008/12/22)
The indium enolate generated from indium(I) bromide and α,α-dichloroacetophenone reacts with aldehydes to produce (syn + anti)-2-chloro-3-hydroxy-propan-1-ones which can be converted to their trans-prop-2-en-1-ones derivatives upon reaction with an extra equivalent of InBr. The enones undergo Michael-induced ring closure reactions with an extra equivalent of the initial enolate to afford the corresponding cyclopropane derivatives, according to a sequenced reaction mechanism.
The direct preparation of functionalised cyclopropanes from allylic alcohols or α-hydroxyketones using tandem oxidation processes
McAllister, Graeme D.,Oswald, Magalie F.,Paxton, Richard J.,Raw, Steven A.,Taylor, Richard J.K.
, p. 6681 - 6694 (2007/10/03)
New manganese dioxide-mediated tandem oxidation processes (TOPs) have been developed, which facilitate the direct conversion of allylic alcohols and α-hydroxyketones into polysubstituted functionalised cyclopropanes. In the simplest version, the oxidation of an allylic alcohol is carried out in the presence of a stabilised sulfurane, and the intermediate α,β-unsaturated carbonyl compound undergoes in situ cyclopropanation. By using a combination of stabilised phosphorane and sulfurane, the direct conversion of allylic alcohols or α-hydroxyketones into functionalised cyclopropanes is achieved, with in situ cyclopropanation being followed by Wittig olefination, or vice versa. The application of these methods to a formal synthesis of the lignan (±)-picropodophyllone, and to novel analogues of the insecticide allethrin II, is described.
The formation of cyclopropane derivatives bearing 1,2-dicarbonyl groups through tandem Michael-Favorskii-type reactions with (E) -β-styrylselenonium triflate
Watanabe, Shin-Ichi,Nakayama, Ippei,Kataoka, Tadashi
, p. 1493 - 1496 (2007/10/03)
A novel tandem Michael-Favorskii-type reaction is described. Treatment of active methylene carbanions, prepared by the reaction of NaH and active methylene compounds, with (E)-β-styrylselenonium triflate in DMF at 70°C for 3 h gave cyclopropane derivatives bearing 1,2-dicarbonyl groups in moderate to good yields. On the other hand, the carbanions derived from malonates reacted with the selenonium salt to afford 1,1-dicarbonylcyclopropane compounds in good yields. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
Triphenylbismuthonium 2-Oxoalkylide, A Moderately Stabilized Bismuthonium Ylide: Generation and Reactions with Some Electrophiles
Matano, Yoshihiro
, p. 2703 - 2710 (2007/10/02)
Treatment of (2-oxoalkyl)triphenylbismuthonium tetrafluoroborates 3 with potassium tert-butoxide in tetrahydrofuran at -78 deg C produced triphenylbismuthonium 2-oxoalkylides 4, which readily underwent epoxidation with the aldehydes 5 to give the α,β-epoxy ketones 7 with highly trans selectivity.The ylide 4a reacted with dimedone 11, the sulfonic acid 13, the thiol 15 and the isocyanate 17 to afford the corresponding ketones 12, 14, 16 and 19 in moderate to good yields.Reaction of the ylide 4c with the α,β-unsaturated ketones 10 and 21 afforded the 1,2-dibenzoyl- and the 1,2,3-tribenzoyl- cyclopropanes 20 and 22, respectively, although the yields were low.In the presence of a catalytic amount of nitrosobenzene 23, the ylide 4a a unique decomposition to give the 2,2,7,7-tetramethyloct-4-ene-3,6-dione 24 in quantitative yield, while the reaction with the nitrile oxide 25 yielded the isoxazoline 26.In all of these reactions, triphenylbusmuthane 6 was the additional major product.
Phase-Transfer-Catalyzed Cyclopropanation. Synthesis of 1,2-Dibenzoyl-3-arylcyclopropanes
Reddy, D. Bhaskar,Reddy, B. Venkataramana,Seshamma, T.,Reddy, N. Subba,Reddy, M. V. Ramana
, p. 289 - 290 (2007/10/02)
The 1,t-2,t and 1,t-2,c-isomers of 1,2-dibenzoyl-3-phenylcyclopropanes have been prepared by the cycloaddition of carbonyl-stabilized sulfur ylides to trans-chalcones under phase-transfer conditions.The configurations of the isomers were characterized by
Studies on Stabilized ?-Sulphuranes: Cyclopropanation with Dimethylphenacylidenesulphurane
Tewari, R. S.,Awasthi, A. K.
, p. 155 - 156 (2007/10/02)
Dimethylphenacylidenesulphurane (2), a stabilized ?-sulphurane has been prepared and reacted with a variety of substituted α,β-unsaturated ketones to afford 1,2,3-triaryl substituted cyclopropanes in fair to good yields.The structural assignments are based on spectral analysis.
