Active Cyclopropane Research Articles

Cyclopropanation reactions catalysed by copper and rhodium complexes homogeneous and heterogenised on a modified USY-zeolite. Influence of the catalyst on the catalytic profile

The reaction of alkyl diazoacetate (ethyl and t-butyl diazoacetate) with styrene and 1,2-dihydropyrane is catalysed by Cu- and Rh-complexes, homogeneous and heterogenised on a modified USY-zeolite. A comparative study (homogeneous vs. supported) was made for the catalytic activity and selectivity in cyclopropanation reactions. High activities and selectivity (cyclopropanation vs. dimerisation) were obtained at 1:150 catalyst:substrate relationship, with the Cu catalysts being remarkably more active than the Rh-ones. The enantioselectivity in the tested conditions was low. The reactivity and selectivity for zeolite-heterogenised catalysts do not deviate significantly from that obtained using the corresponding homogeneous complexes, though they could be used without loss of cyclopropanation activity and metal leaching at least in five successive runs.

Efficient Suzuki-Type Cross-Coupling of Enantiomerically Pure Cyclopropylboronic Acids.

Optically active cyclopropanes (e.g. 1) can be prepared by the use of tartaric acid derivatives as chiral auxiliaries in the palladium-catalyzed cross-coupling of optically active cyclopropylboronic acids with electrophiles. The absolute configuration of the chiral carbon atom is retained, and the reaction proceeds with good yields and enantiomeric excesses. R=H, p-Ph, o-CO2 CH3 , p-CO2 CH3 , p-NO2 , o-OCH3 , m-OCH3 .

ChemInform Abstract: A Stereoselective Synthesis of Optically Active Cyclopropanes by Tandem Alkylation and SN′ Cyclization.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A Stereoselective Synthesis of Optically Active Cyclopropanes by Tandem Alkylation and SN, Cyclization

Some optically active cyclopropanes were synthesized by using 2-hydroxypinan-3-one as a chiral auxiliary to form a chiral ketimine and followed by Pd(0) catalyzed tandem alkylation and SN, cyclisation of 1,4-dichlorobut-2-ene with chiral ketimines. The yields were about 70% and the diastereoselectivities of reaction were 100%.

Carbon−Carbon Bond Activation of Cyclopropane by Subsurface Hydrogen on the Ni(111) Surface

Carbon−carbon bond activation by subsurface hydrogen has been observed for adsorbed cyclopropane at 170 K on the Ni(111) surface. Propane was the dominant product, and no multiple C−C bond activation processes were observed. Cyclopropane desorbs at 124 K from both the clean and the hydrogen-coadsorbed Ni(111) surface. Neither coadsorbed hydrogen nor disproportionation induces propane formation. These observations are consistent with previous results that energetic forms of hydrogen are necessary to activate the C−C bond even in strained cyclopropane under ultrahigh-vacuum conditions.

Biologically Active Cyclopropanes and Cyclopropenes

Abstract: The variety of biological systems which are modulated by naturally occurring cyclopropanes has only been realized recently. They range from antibiotic, antiviral, antifungal and insecticidal activities, control of plant growth and fruit ripening, antimycotic, thyromimetic, hormonal, carcinogenic or antitumoral activities, enzyme and gluconeogenesis inhibitions, to neuro­ chemical activity. Cyclopropanes are also major components of membranes, for instance in tuberculosis cells, and key intermediates in many biosynthetic processes. Many synthetic drugs include cyclopropanes in their structure and they are also widely used to probe the mechanisms of biological processes. Naturally occurring cyclopropenes are known to be potent enzyme inhibitors controlling key processes on the fatty acid desaturation cycle and, in one case, to be an antibacterial agent. Synthetic analogues similarly inhibit pheromone production in insects, and the production of bacterial membranes, and interfere with the behaviour of insects by blocking pheromone receptors. When they have been demonstrated, the mechanisms responsible for the specific bioactivity of these systems are also reviewed.

シクロプロパンアミノ酸の合成と立体制約因子としての生理活性ペプチドへの導入

Cyclopropane amino acids are the amino acid derivatives which contain the cyclopropane ring in their side chain. Various cyclopropane amino acids were isolated from many different natural sources. Along with many efforts to synthesize these natural compounds, studies on the structure-activity relationships of bioactive peptides have highlighted the usefulness of cyclopropane amino acids. Incorporation of cyclopropane amino acids has been achieved for some neuropeptides, hormones, and enzyme inhibitors and these sterically rigid cyclopropane amino acids were found to be a key constituent not only as conformational constraint but also as a structural element to avoid enzymatic degradations. Several distinct success stories have prompted organic chemists to challenge the asymmetric synthesis of optically active cyclopropane amino acids in these years.

Synthesis of optically active cis- and trans-1,2-disubstituted cyclopropane derivatives by the Simmons-Smith reaction of allyl alcohol derivatives derived from (R)-2,3-O-isopropylideneglyceraldehyde

The Simmons-Smith reactions of Z- and E-allyl alcohol derivatives 6 derived from (R)-2,3-O-isopropylideneglyceraldehyde (6) were used for the synthesis of optically active cis- and trans-1,2-disubstituted cyclopropane derivatives. Reaction of 6 with diethyl zinc and diiodomethane gave cyclopropane derivatives 7 in 84% to quantitative yields with 35 to ≃100% des. Identical facial selectivities toward the double bonds, 1re-2si for Z-6 and 1re-2re for E-6, were observed in the cyclopropanations. The diastereoselectivity was dependent on the protecting group on the terminal allylic oxygen (R of 6, TBDPS>MOM>Bn) and on the stereochemistry of the double bond (Z >E). For TBDPS ethers Z-and E-6c, cis- and trans-7c were obtained as single distereomers, respectively. It was clearly demonstrated that the stereoselectivity of the cyclopropantion is controlled by the directing effect of the allylic oxygen (O-1) of the dioxolane ring, which coordinates to the reagent. The terminal allylic oxygen (O-2) lowered the diastereoselectivity. This reaction was applied to the synthesis of optically active cyclopropane analogs of γ-aminobutyric acid (GABA) 18,22, and ent-22

Optically active cyclopropanes

Optically active cyclopropanes

ChemInform Abstract: A Novel Asymmetric Synthesis of Substituted Cyclopropanes.

AbstractThe chiral, nonracemic bicyclic lactams (I) are used to prepare the optically active cyclopropanes (V).

ChemInform Abstract: Semicorrin Metal Complexes as Enantioselective Catalysts. Part 2. Enantioselective Cyclopropane Formation from Olefins with Diazo Compounds Catalyzed by Chiral (Semicorrinato)copper Complexes.

AbstractCopper complexes of chiral semicorrin ligands (preparation described in the preceding paper) are found to be efficient catalysts for the preparation of optically active cyclopropanes such as (III) and (IV) from the alkenes (I) and the diazo compounds (II).

ChemInform Abstract: Vibrational Circular Dichroism of Optically Active Cyclopropanes. Part 3. trans‐2‐Phenylcyclopropanecarboxylic Acid Derivatives and Related Compounds

ChemInformVolume 18, Issue 34 Physical Organic Chemistry ChemInform Abstract: Vibrational Circular Dichroism of Optically Active Cyclopropanes. Part 3. trans-2-Phenylcyclopropanecarboxylic Acid Derivatives and Related Compounds S. C. YASUI, Dep. Chem., Univ. Ill., Chicago, IL 60607, USASearch for more papers by this authorT. A. KEIDERLING, Dep. Chem., Univ. Ill., Chicago, IL 60607, USASearch for more papers by this author S. C. YASUI, Dep. Chem., Univ. Ill., Chicago, IL 60607, USASearch for more papers by this authorT. A. KEIDERLING, Dep. Chem., Univ. Ill., Chicago, IL 60607, USASearch for more papers by this author First published: August 25, 1987 https://doi.org/10.1002/chin.198734059Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume18, Issue34August 25, 1987 RelatedInformation

Synthesis and structure of cis-PtX 2(P(t-Bu) 2CH 2CH 2CHCHCH 3) (X = Cl, Br), A platinum π-olefin complex formed by the intramolecular activation of a cyclopropylphosphine

The mixed chloro/bromo π-olefin complexes cis-PtX 2 (P(t-Bu) 2CH 2CH 2CHCHCH 3) ) 2) have been prepared by the reaction of Zeise's salt (K[PtCl 3(C 2H 4)]) with P(t-Bu) 2(CH 2CH 2 CHCH 2CH 2) · HBr in boiling ethanol. The dimer complexes [PtX(P(t-Bu) 2CH 2CH 2 CHCH 2CH 2)] 2 (μ-X)(μ-Y) ( 1) (X, Y  Cl or Br) form first with subsequent activation of cyclopropane to give the monomeric π-olefin complexes ( 2). The mixed π-olefin complexes 2 co-crystallize. The average structure of 2 has been determined by X-ray methods. The relative occupanies in bromine for halogen sites cis- and trans- to coordinated olefin are 0.464(6) and 0.256(6), respectively. The olefin is symmetrically bound to the Pt atom (PtC 2.17(1) Å). The olefinic CC bond length is 1.38(1) Å.

Vibrational circular dichroism of optically active cyclopropanes. 3. trans-2-Phenylcyclopropanecarboxylic acid derivatives and related compounds

Vibrational circular dichroism of optically active cyclopropanes. 3. trans-2-Phenylcyclopropanecarboxylic acid derivatives and related compounds

Catalytic asymmetric synthesis of cyclopropanecarboxylic acids: an application of chiral copper carbenoid reaction

Abstract

Chiroptical properties and optical and molecular orbital calculations for dictyopterenes A and B

Circular dichroism spectra of the optically active cyclopropane hydrocarbons (1a) and (2), measured over a range of temperatures, showed these compounds to be configurationally identical. The c.d. spectrum was found to consist of two overlapping exciton pairs, corresponding to an equilibrium mixture of two solution conformers, for which thermodynamic parameters were calculated.

Transition metal carbene complexes : LIII. Proof of the absence of a free carbene in the preparation of a cyclopropane from a metal-carbene complex

By using an optically active metal-carbene complex we were able to isolate an optically active cyclopropane from the reaction of diethyl fumarate with [(−) ( R)-methylphenylpropylphosphine] (phenylmethoxycarbene) tetracarbonylchromium. In addition to being synthetically useful for the preparation of cyclopropanes of optical activity, this reaction demonstrates that no free carbene is involved in the mechanism for the reaction.

New halocyclopropane insecticides and the mode of action of DDT.

A steric theory of DDT action has led to the design of some new and highly active cyclopropane insecticides. The new compounds suggest a general van der Waals model for diaryl insecticides and support a theory of insecticide action based on the sodium pores of nerve membranes.

Chemistry of sulfoxides and related compounds. XV. Synthesis of optically active cyclopropanes and oxiranes using an optically active oxosulfonium methylide

Chemistry of sulfoxides and related compounds. XV. Synthesis of optically active cyclopropanes and oxiranes using an optically active oxosulfonium methylide

Structure of Malvalic Acid and Some Related C18 and C19 Cyclopropane Fatty Acids

IN recent years an interesting group of fatty acids containing a cyclopropane or a cyclopropene ring has been isolated from natural products or synthesized. This work followed the discovery by Hofmann et al. 1,2 of a biologically active C19H36O2 cyclopropane fatty acid, lactobacillic acid, in the lipides of Lactobacillus arabinosus and L. casei. Four more C19 acids of this type were synthesized3,4—the DL, cis and trans, 9-10 and 11-12, methylene octadecanoic acids. The crystal structures of two of these racemates have been studied5,6, namely, the DL trans 9-10 and DL cis 11-12, and shown to have the characteristic straight- and bent-chain configurations illustrated in the electron density Fourier projections in Figs. 1 and 2. From the similarity in the diffraction data, the other two racemates are believed to be structurally isomorphous7 in the trans and cis series, respectively. Of these, the DL cis 9-10 acid was shown7 to be identical with the dihydrosterculic acid obtained4 by hydrogenation of the sterculic acid8, C19H34O2, from the kernel oil of the tropical tree Sterculia foetida.