Cyclopropene derivatives of aminosugars for metabolic glycoengineering

• Jessica Hassenrück and
• Valentin Wittmann

Beilstein J. Org. Chem. 2019, 15, 584–601, doi:10.3762/bjoc.15.54

• of reference compounds. Furthermore, their structure was expected to resemble that of the cyclopropenes as close as possible providing valuable information on the metabolic acceptance although it has to be kept in mind that (methyl)cyclopropanes are not plane in contrast to cyclopropenes. Scheme 2

Dirhodium(II)-catalyzed [3 + 2] cycloaddition of N-arylaminocyclopropane with alkyne derivatives

• Wentong Liu,
• Yi Kuang,
• Zhifan Wang,
• Jin Zhu and
• Yuanhua Wang

Beilstein J. Org. Chem. 2019, 15, 542–550, doi:10.3762/bjoc.15.48

• cycloaddition protocol. Keywords: [3 + 2]; alkyne; cycloaddition; cyclopropanes; dirhodium catalysis; N-arylaminocyclopropanes; Introduction N-Arylaminocyclopropanes 1 are important structural motifs for pharmaceuticals and are found especially in marketed fluoroquinolone antibiotics [1], such as

Sigmatropic rearrangements of cyclopropenylcarbinol derivatives. Access to diversely substituted alkylidenecyclopropanes

• Guillaume Ernouf,
• Jean-Louis Brayer,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2019, 15, 333–350, doi:10.3762/bjoc.15.29

• substrate scope and some applications of the products arising from those reactions, are presented in this review. Keywords: alkylidenecyclopropanes; cyclopropanes; cyclopropenes; sigmatropic rearrangements; strained rings; Introduction Among the ever expanding diversity of chemical transformations

• involving cyclopropenes, which are largely dominated by ring-cleavage processes to access functionalized acyclic compounds or to construct new carbocycles or heterocycles, those reactions that preserve the three-membered ring and enable access to diversely substituted cyclopropanes or

• alkylidenecyclopropanes are also synthetically useful [1][2][3][4][5][6]. The importance of this latter class of transformations is obviously related to the widespread occurrence of cyclopropanes in natural and/or bioactive compounds [7][8] and the great interest of the cyclopropyl core in new drugs development [9

Synthesis of 1,2-divinylcyclopropanes by metal-catalyzed cyclopropanation of 1,3-dienes with cyclopropenes as vinyl carbene precursors

• Jesús González,
• Alba de la Fuente,
• María J. González,
• Laura Díez de Tejada,
• Luis A. López and
• Rubén Vicente

Beilstein J. Org. Chem. 2019, 15, 285–290, doi:10.3762/bjoc.15.25

• in medicinal chemistry [4][5][6]. Likewise, due to its unique structure and bond properties, cyclopropanes have exclusive yet useful synthetic utilities [7], which are closely connected with the substitution pattern. For instance, the presence of vinyl groups directly attached to a cyclopropane ring

• cyclopropanes contrasts with the existence of few straightforward routes for their syntheses. Typical methods rely on the use of reagents containing the required cyclopropane ring, which involve multistep sequences for the installation of adequate functionalization. Thus, Wittig-type olefination with

• of cyclic dienes allowed the synthesis of the corresponding 1,2-divinylcyclopropanes with good-to-complete endo selectivity. In contrast, acyclic dienes were also efficiently converted into the expected cyclopropanes but with low cis/trans selectivities. In general, simple ZnCl2 and [Rh2(OAc)4

Synthesis, biophysical properties, and RNase H activity of 6’-difluoro[4.3.0]bicyclo-DNA

• Sibylle Frei,
• Adam K. Katolik and
• Christian J. Leumann

Beilstein J. Org. Chem. 2019, 15, 79–88, doi:10.3762/bjoc.15.9

• conducted. This experiment revealed that the oligonucleotide containing five modified units was able to elicit the RNase H-mediated cleavage of the complementary RNA strand. Keywords: DNA/RNA affinity; fluorinated cyclopropanes; fluorinated nucleic acids; RNase H activity; sugar modified nucleosides

Gold-catalyzed ethylene cyclopropanation

• Silvia G. Rull,
• Andrea Olmos and
• Pedro J. Pérez

Beilstein J. Org. Chem. 2019, 15, 67–71, doi:10.3762/bjoc.15.7

• formation of electrophilic metal–carbene intermediates LnM=CRR’ [1][2] that further react with nucleophiles such as olefins en route to cyclopropanes. However, these intermediates can also react with another molecule of the diazo reagent promoting the formation of olefins RR’C=CRR’ [17]. This side reaction

• spectroscopy. It is worth mentioning that when diethyl diazomalonate or ethyl 2-phenyldiazoacetate were employed as the carbene precursor, no cyclopropanes were detected, only olefins formed from carbene dimerization as well as unreacted diazo compounds were identified at the end of the reaction. Conclusion We

6’-Fluoro[4.3.0]bicyclo nucleic acid: synthesis, biophysical properties and molecular dynamics simulations

• Sibylle Frei,
• Andrei Istrate and
• Christian J. Leumann

Beilstein J. Org. Chem. 2018, 14, 3088–3097, doi:10.3762/bjoc.14.288

• modification might be a substrate for RNase H. Keywords: DNA/RNA affinity; fluorinated cyclopropanes; fluorinated nucleic acids; molecular dynamics simulations; sugar modified nucleosides; Introduction A powerful strategy for the treatment of various disorders like cancer, viral and inherited diseases is the

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• to the synthesis of benzofulvalanes 49 and 50 from the reaction of 4,5-benzotropone (11) with corresponding cyclopropanes [60][61]. While the reaction of 4,5-benzotropone (11) with malononitrile afforded 8,8-dicyano-3,4-benzoheptafulvalene (51) [62], the condensation of 4,5-benzotropone (11) with

One-pot sequential synthesis of tetrasubstituted thiophenes via sulfur ylide-like intermediates

• Jun Ki Kim,
• Hwan Jung Lim,
• Kyung Chae Jeong and
• Seong Jun Park

Beilstein J. Org. Chem. 2018, 14, 243–252, doi:10.3762/bjoc.14.16

• center and the substituents on the sulfur atom [10]. In general, these reagents are often applied in the preparation of simple small rings [13], such as epoxides [14][15][16][17][18], cyclopropanes [19][20][21][22], aziridines [23], indoles [24], pyrroles [24], and indolines [25]. In addition, other

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• similar transfer of a carbene unit was presented to explain the formation of cyclopropanes 15 in the reaction of E- and Z-1b with the in situ generated thiocarbonyl S-isopropanide 16a. The latter is formed through a thermal N2 elimination from 2,5-dihydro-1,3,4-thiadiazole 17a [24][25] (Scheme 5). The

• mixtures of isomeric cyclopropanes were obtained in each case. The trans and cis-isomers of cyclopropane 15 were also obtained in reactions of 2-diazopropane with E-1b and Z-1b, respectively [25]. In that case, the formation of the cyclopropanes was stereospecific. The formation of mixtures of thiolanes of

• type 19 and cyclopropanes of type 15 in which Me2C is replaced by H2C was observed when the sterically hindered S-methanide derived from 2,2,6,6-tetramethylcyclohexanethione was reacted with E- or Z-1b [26], whereas in the cases of 2,2,5,5-tetramethylcyclopentanethione and 1,1,3,3-tetramethylindane-2

Phenylsilane as an effective desulfinylation reagent

• Wanda H. Midura,
• Aneta Rzewnicka and
• Jerzy A. Krysiak

Beilstein J. Org. Chem. 2017, 13, 1513–1517, doi:10.3762/bjoc.13.150

• were connected with the synthesis and further conversion of multifunctional cyclopropanes, where the carboxylate moiety was present in close proximity to sulfinyl and phosphoryl substituents [18][19][20]. A selective and effective method of the independent conversion of each of these substituents is

• reduction of the ester group. In both cyclopropanes the carboxylate moiety and the sulfinyl group were in vicinal relation, but in 1, formed in the reaction of vinyl phosphoryl sulfoxide with EDSA [22], the ester group was easily accessed, since the bulky phosphoryl group was also in vicinal position to the

• conditions with a large excess of silyl reagent (procedure 1) occurred with full conversion of the cyclopropanes, although some problems with the isolation of the product due to an excess of silane induced a modification of the reduction procedure. The gain of using THF as a solvent [17] (procedure 2) let us

Exploring endoperoxides as a new entry for the synthesis of branched azasugars

• Svenja Domeyer,
• Mark Bjerregaard,
• Henrik Johansson and
• Daniel Sejer Pedersen

Beilstein J. Org. Chem. 2017, 13, 644–647, doi:10.3762/bjoc.13.63

• strategies have since been developed, including asymmetric and chemoenzymatic methods [2][6][7][8]. Substituted endoperoxides have been applied to the synthesis of substituted cyclopropanes, furans and carbohydrates [9][10][11][12]. Inspired by the work of Robinson and co-workers [10][11][12] we hypothesised

Unpredictable cycloisomerization of 1,11-dien-6-ynes by a common cobalt catalyst

• Abdusalom A. Suleymanov,
• Dmitry V. Vasilyev,
• Valentin V. Novikov,
• Yulia V. Nelyubina and
• Dmitry S. Perekalin

Beilstein J. Org. Chem. 2017, 13, 639–643, doi:10.3762/bjoc.13.62

• ]. In particular, cycloisomerization of enynes allows one to prepare compounds with exocyclic double bonds and cyclopropanes in a highly selective manner [5][6][7]. While catalytic transformations of enynes have been investigated in detail, there are only a few examples of similar reactions of dienynes

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• rhodium(II) complex 220 followed by the carboxylic methyl ester hydrolysis/decarboxylation in DMSO/H2O at 120 °C with up to 72% enantiomeric excess (Scheme 60) [89]. 1.7 From epoxides and cyclopropanes The chalcone epoxides 221 ring opening catalyzed by indium(III) chloride, followed by a intramolecular

Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl S-methanides as diradical processes: a computational study

• Michael L. McKee,
• Grzegorz Mlostoń,
• Katarzyna Urbaniak and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 410–416, doi:10.3762/bjoc.13.44

• case of similar thiocarbonyl S-isopropanides, the intermediate zwitterions, formed in the course of the attempted [3 + 2]-cycloaddition with electron-deficient ethenes, undergo 1,3-electrocyclization yielding mixtures of stereoisomeric cyclopropanes in addition to the expected 5-membered thiolanes

Synergistic chiral iminium and palladium catalysis: Highly regio- and enantioselective [3 + 2] annulation reaction of 2-vinylcyclopropanes with enals

• Haipan Zhu,
• Peile Du,
• Jianjun Li,
• Ziyang Liao,
• Guohua Liu,
• Hao Li and
• Wei Wang

Beilstein J. Org. Chem. 2016, 12, 1340–1347, doi:10.3762/bjoc.12.127

• ; Introduction The power of “donor–acceptor” (D–A) cyclopropanes as versatile 1,3-dipolar components is fuelled by its capacity of serving a complementary approach to a wide array of 5-membered ring structures, which are difficult or impossible to access by classic [3 + 2] cycloaddition reactions [1][2][3][4][5

• ][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. In recent years, significant efforts have been devoted to developing a catalytic enantioselective version of the processes. In this context, the D–A cyclopropanes have been applied for

• important challenges. To the best of our knowledge, so far merely two catalyst manifolds have been realized to effect the transformations with C=C double bonds instead of C=O in the α,β-unsaturated systems. Tsuji described the first organometallic promoted non-asymmetric reaction between D–A cyclopropanes

From steroids to aqueous supramolecular chemistry: an autobiographical career review

• Bruce C. Gibb

Beilstein J. Org. Chem. 2016, 12, 684–701, doi:10.3762/bjoc.12.69

• spectroscopic difference between these molecules and how these compared to analogous steroids whereby the cyclopropane group in the A-ring is replaced with a conjugating C=C double bond. To cut a long story short, vinyl cyclopropanes are conjugated, albeit to a lesser degree than dienes, and NMR, IR and UV–vis

Evidencing an inner-sphere mechanism for NHC-Au(I)-catalyzed carbene-transfer reactions from ethyl diazoacetate

• Manuel R. Fructos,
• Juan Urbano,
• M. Mar Díaz-Requejo and
• Pedro J. Pérez

Beilstein J. Org. Chem. 2015, 11, 2254–2260, doi:10.3762/bjoc.11.245

• )phenyl)borate) as a halide scavenger, induced the incorporation of the :CHCO2Et group from N2CHCO2Et to styrene (Scheme 2a) or methanol (Scheme 2b), among others. With the former, in addition to the formation of the expected cyclopropanes, a second type of product was observed, derived from the

Coupling of α,α-difluoro-substituted organozinc reagents with 1-bromoalkynes

• Artem A. Zemtsov,
• Alexander D. Volodin,
• Vitalij V. Levin,
• Marina I. Struchkova and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2015, 11, 2145–2149, doi:10.3762/bjoc.11.231

• ][11]. Alternatively, functional group manipulations starting from available CF2-containing building blocks can be considered, but multistep sequences render this approach laborious [12][13][14]. Difluoro-substituted cyclopropanes and cyclopropenes constitute a specific class of compounds accessible by

Organic chemistry on surfaces: Direct cyclopropanation by dihalocarbene addition to vinyl terminated self-assembled monolayers (SAMs)

• Malgorzata Adamkiewicz,
• David O’Hagan and
• Georg Hähner

Beilstein J. Org. Chem. 2014, 10, 2897–2902, doi:10.3762/bjoc.10.307

• the resultant dienes [19]. We are not aware however of straightforward carbene additions having been explored with olefin-terminated SAMs. The potential for product cyclopropanes offered a modification of limited steric impact, but if suitably substituted may be used to tune surface properties

(2R,1'S,2'R)- and (2S,1'S,2'R)-3-[2-Mono(di,tri)fluoromethylcyclopropyl]alanines and their incorporation into hormaomycin analogues

• Armin de Meijere,
• Sergei I. Kozhushkov,
• Dmitrii S. Yufit,
• Christian Grosse,
• Marcel Kaiser and
• Vitaly A. Raev

Beilstein J. Org. Chem. 2014, 10, 2844–2857, doi:10.3762/bjoc.10.302

• (fluoromethylcyclopropyl)alanine moieties have been synthesized and subjected to preliminary tests of their antibiotic activity. Keywords: amino acids; biosynthesis; building blocks; cyclopropanes; natural products; synthetic methods; Introduction The intermolecular signal metabolite hormaomycin (1, Figure 1) was first

Visible light mediated intermolecular [3 + 2] annulation of cyclopropylanilines with alkynes

• Theresa H. Nguyen,
• Soumitra Maity and
• Nan Zheng

Beilstein J. Org. Chem. 2014, 10, 975–980, doi:10.3762/bjoc.10.96

• ; visible light; Introduction Cyclopropanes have been used as a three-carbon synthon to prepare a diverse array of organic compounds [1][2][3][4]. The unusual reactivity, exhibited by cyclopropanes, is largely due to their inherent ring strain that makes cleavage of the C–C bonds facile [5]. A number of

• methods have been developed to regioselectively cleave cyclopropanes, generating synthetically useful intermediates that can be further manipulated [1][2][3][4][5]. For one subclass of cyclopropanes, cyclopropylamines, the requisite ring opening is often accomplished by one-electron oxidation of the

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

• -catalyzed process described in Scheme 31 takes advantage of the usual formation of 43 which undergoes a [3 + 3]-cycloaddition reaction with cyclopropanes 59 under nickel perchlorate catalysis. Cycloaddition reactions of activated cyclopropanes with nitrones under Lewis acid catalysis have been previously

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• the oxidation of cyclopropanes by oxygen in the presence of transition-metal salts as the catalysts. The reactions of bicycloalkanols 10a–e with singlet oxygen in the presence of catalytic amounts of Fe(III) acetylacetonate produce peroxides 12a–e, which can also be synthesized starting from silylated

• %. Trifluoromethyl-containing dioxolane 25 (Figure 3) was synthesized according to this method in 40% yield [239]. A series of 1,2-dioxolanes 27a–e containing various functional groups R were prepared by the oxidation of cyclopropanes 26a–e (Scheme 9, Table 4). The reaction was performed in the presence of Ph2Se2

• (10 mol %) and azobisisobutyronitrile (AIBN, 8 mol %) in air under irradiation for two days. The product was purified by flash chromatography to obtain a mixture of cis and trans isomers, whose ratio depends primarily on the nature of the substituent in cyclopropanes 26a–e [240]. The oxidation of

The chemistry of amine radical cations produced by visible light photoredox catalysis

• Jie Hu,
• Jiang Wang,
• Theresa H. Nguyen and
• Nan Zheng

Beilstein J. Org. Chem. 2013, 9, 1977–2001, doi:10.3762/bjoc.9.234

• initialize radical polymerization of HEA. Because of ring strain, cyclopropanes are prone to ring opening via cleavage of one of the three C–C bonds. The resulting reactive intermediates have been shown to participate in a number of synthetic/mechanistic applications [103][104]. One of these applications is