Iron-catalyzed decarboxylative alkenylation of cycloalkanes with arylvinyl carboxylic acids via a radical process

• Jincan Zhao,
• Hong Fang,
• Jianlin Han and
• Yi Pan

Beilstein J. Org. Chem. 2013, 9, 1718–1723, doi:10.3762/bjoc.9.197

• carbon–carbon or carbon–heteroatom bonds in a highly atom economical manner [1][2][3][4][5][6][7][8]. Among all these C–H functionalization methods, the direct C(sp3)–H functionalization attracts particular attention due to its low reactivity and challenging activation [9][10][11]. In previous studies

Re₂O₇-catalyzed reaction of hemiacetals and aldehydes with O-, S-, and C-nucleophiles

• Wantanee Sittiwong,
• Michael W. Richardson,
• Charles E. Schiaffo,
• Thomas J. Fisher and
• Patrick H. Dussault

Beilstein J. Org. Chem. 2013, 9, 1526–1532, doi:10.3762/bjoc.9.174

• that different levels of activation are required for trapping by heteroatom versus carbon nucleophiles. Previous work established that the perrhenate-catalyzed isomerization of alcohols can also employ silyl ethers as substrates [25], and our work demonstrates that the same is true for the hemiacetals

Electron self-exchange activation parameters of diethyl sulfide and tetrahydrothiophene

• Martin Goez and
• Martin Vogtherr

Beilstein J. Org. Chem. 2013, 9, 1448–1454, doi:10.3762/bjoc.9.164

• all published studies of electron self-exchange – apart from indirect determinations based on the Marcus cross relationship [2] – have been carried out on aromatic or olefinic substrates. All known aliphatic radical cations are heteroatom-centered, which considerably increases the mechanistic

• compound. Which sulfide-derived intermediate is the source of CIDNP can be concluded from the the polarization pattern, i.e., from the relative polarization intensities of the different protons; ethyl groups are very convenient for this type of analysis [36]. In an ethyl-substituted heteroatom-centered

• radical cation, such as DES•+, only the α protons experience an appreciable hyperfine coupling, so only these protons can acquire polarizations. In contrast, for an α (heteroatom) substituted ethyl radical, e.g., both the α and the β protons possess large hyperfine coupling constants, which are negative

Homolytic substitution at phosphorus for C–P bond formation in organic synthesis

• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 1269–1277, doi:10.3762/bjoc.9.143

• review article covers emerging, powerful synthetic approaches to organophosphorus compounds by homolytic substitution at phosphorus with a carbon-centered radical. Phosphination reagents include diphosphines, chalcogenophosphines and stannylphosphines, which bear a weak P–heteroatom bond for homolysis

Transition-metal and organocatalysis in natural product synthesis

• David Yu-Kai Chen and
• Dawei Ma

Beilstein J. Org. Chem. 2013, 9, 1192–1193, doi:10.3762/bjoc.9.134

• the history of chemical science. These transformations, largely concerning carbon–carbon/carbon–heteroatom bond formations, asymmetric induction, and catalysis, constantly expand the repertoire of powerful tools available at the organic chemist’s disposal, and enable more challenging synthetic

Cascade radical reaction of substrates with a carbon–carbon triple bond as a radical acceptor

• Hideto Miyabe,
• Ryuta Asada and
• Yoshiji Takemoto

Beilstein J. Org. Chem. 2013, 9, 1148–1155, doi:10.3762/bjoc.9.128

• chiral Lewis acid and these substrates. Keywords: cascade; cyclization; enantioselective; free radical; Lewis acid; radical; Introduction Strategies involving a cascade process offer the advantage of multiple carbon–carbon and/or carbon–heteroatom bond formations in a single operation. Radical

• ][30][31][32][33][34][35][36]. We have also directed our efforts toward the development of new and efficient cascade approaches for the construction of carbon–carbon/heteroatom bonds based on radical chemistry. These approaches can be classified into two categories according to their reaction mechanism

Conformational analysis and intramolecular interactions in monosubstituted phenylboranes and phenylboronic acids

• Josué M. Silla,
• Rodrigo A. Cormanich,
• Roberto Rittner and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2013, 9, 1127–1134, doi:10.3762/bjoc.9.125

• highly stabilizing. Surprisingly, good electron donors, such as the nitrogen-containing phenylboranes, exhibit a conformation with the heteroatom lone pair directed toward the empty orbital of boron; this is the case for 7c, 8b and 9c. Despite not being appreciably populated (high energy in Table 5

Amyloid-β probes: Review of structure–activity and brain-kinetics relationships

• Todd J. Eckroat,
• Abdelrahman S. Mayhoub and
• Sylvie Garneau-Tsodikova

Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116

• brain uptake, its washout rate was increased compared to its dimethylamine counterpart [47]. Interestingly, changing the heteroatom order in the central ring from 1,3,4 (50a–f) to 1,2,4 (51a–e) has great effects on both the physical characteristics and pharmacokinetics of the compounds. The 3,5-diphenyl

Methylidynetrisphosphonates: Promising C₁ building block for the design of phosphate mimetics

• Vadim D. Romanenko and
• Valery P. Kukhar

Beilstein J. Org. Chem. 2013, 9, 991–1001, doi:10.3762/bjoc.9.114

• heteroatom substituent at the bridged carbon atom permits both modulation of pKa values and hydrogen bonding, there is a need for profound study of α-functionalized trisphosphonate systems. Such compounds can be promising building blocks for the synthesis of false substrates or enzyme inhibitors involved in

Design and synthesis of tag-free photoprobes for the identification of the molecular target for CCG-1423, a novel inhibitor of the Rho/MKL1/SRF signaling pathway

• Jessica L. Bell,
• Andrew J. Haak,
• Susan M. Wade,
• Yihan Sun,
• Richard R. Neubig and
• Scott D. Larsen

Beilstein J. Org. Chem. 2013, 9, 966–973, doi:10.3762/bjoc.9.111

• high-resolution mass-spectral analysis. We selected benzophenone and azide as the PGs for incorporation into 2 based on synthetic ease and their complementary photoreactivities (benzophenone inserts into C–H bonds, azide into heteroatom–H bonds) [12]. Furthermore, we had previously established that

Gold-catalyzed oxycyclization of allenic carbamates: expeditious synthesis of 1,3-oxazin-2-ones

• Benito Alcaide,
• Pedro Almendros,
• M. Teresa Quirós and
• Israel Fernández

Beilstein J. Org. Chem. 2013, 9, 818–826, doi:10.3762/bjoc.9.93

• one heteroatom are rare [43][44][45][46][47][48]. Besides, it has been reported very recently that the Au(I)-catalyzed cyclization of a N-phenethyl-N-Boc-protected allenamide failed [49]. Despite the above precedents, but in continuation of our interest in heterocyclic and allene chemistry [50][51][52

Intramolecular carbonickelation of alkenes

• Rudy Lhermet,
• Muriel Durandetti and
• Jacques Maddaluno

Beilstein J. Org. Chem. 2013, 9, 710–716, doi:10.3762/bjoc.9.81

• amines has been studied to evaluate the influence of the groups borne by the double bond on this cyclization. The results show that when this reaction takes place, it affords only the 5-exo-trig cyclization products, viz. dihydrobenzofurans or indoles. Depending on the tethered heteroatom (O or N), the

Regio- and stereoselective carbometallation reactions of N-alkynylamides and sulfonamides

• Yury Minko,
• Morgane Pasco,
• Helena Chechik and
• Ilan Marek

Beilstein J. Org. Chem. 2013, 9, 526–532, doi:10.3762/bjoc.9.57

• heteroatom [16][17], whereas an acceptor substituent (XR = SR, SOR, SO2R, SiMe3, PR2, P(O)R2, Path A, Scheme 1) would preferably give the α-isomer [16][17] (copper geminated to the heteroatom, Scheme 1). Although N-substituted alkynes are known to give the β-isomer, we thought that a precomplexation of the

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

Intramolecular carbolithiation of N-allyl-ynamides: an efficient entry to 1,4-dihydropyridines and pyridines – application to a formal synthesis of sarizotan

• Wafa Gati,
• Mohamed M. Rammah,
• Mohamed B. Rammah and
• Gwilherm Evano

Beilstein J. Org. Chem. 2012, 8, 2214–2222, doi:10.3762/bjoc.8.250

• constitutes a most efficient entry to polysubstituted alkenes, provided that both the regioselectivity and the stereoselectivity can be controlled [2][3][4][5]. In this context, an efficient strategy to control these selectivity issues is the incorporation of a heteroatom directly attached to the triple bond

• provide most efficient entries to polysubstituted, stereodefined heteroatom-substituted alkenes and has been implemented in remarkably elegant processes [6]. Intramolecular versions are especially attractive and provide most useful entries to highly substituted carbo- and heterocycles. Based on our recent

• synthesis of the anti-dyskinesia agent sarizotan. This new addition to the field of carbometallation reactions extends the chemistry of ynamides and should be useful in heterocyclic and medicinal chemistry as well. Further studies to extend this process to other heteroatom-substituted alkynes and to develop

Mechanochemistry assisted asymmetric organocatalysis: A sustainable approach

• Pankaj Chauhan and
• Swapandeep Singh Chimni

Beilstein J. Org. Chem. 2012, 8, 2132–2141, doi:10.3762/bjoc.8.240

• , which helps in the easy isolation of products. Besides the significant progress in the application of mechanochemical techniques in asymmetric organocatalysis, there exists a lot of scope for other asymmetric reactions ranging from simple carbon–carbon, and carbon–heteroatom bond formation to more

Palladium-catalyzed C–N and C–O bond formation of N-substituted 4-bromo-7-azaindoles with amides, amines, amino acid esters and phenols

• Rajendra Surasani,
• Dipak Kalita,
• A. V. Dhanunjaya Rao and
• K. B. Chandrasekhar

Beilstein J. Org. Chem. 2012, 8, 2004–2018, doi:10.3762/bjoc.8.227

• compounds, pharmaceuticals, fragrances, cosmetics and polymers [11][12][13][14][15][16][17]. Among others Buchwald, Hartwing and co-workers followed by many other groups during the past decade reported the metal-catalyzed formation of carbon–heteroatom bonds [18][19][20][21][22][23][24][25][26][27][28][29

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

• organic synthesis for the first time. All classes of compounds containing at least two allene moieties are considered, starting from simple conjugated bisallenes and ending with allenes in which the two cumulenic units are connected by complex polycyclic ring systems, heteroatoms and/or heteroatom

• in 7 (n = 1) is replaced by a heteroatom, the heteroorganic bisallenes 16 result, in their simplest form as ethers (X = O), amines (X = NR), thioethers (X = S), etc. Analogously bisallenic epoxides (17, X = O) or aziridines (17, X = NR) can formally be generated from the corresponding all-carbon

• and specific approaches, and these will be discussed in due course. 1.2 Synthesis of functionalized systems Derivatives of 2 carrying “real”, i.e. heteroatom-containing functional groups, are comparatively rare and this constitutes one serious drawback of using these electron-rich compounds in

N-Heterocyclic carbene–palladium(II)-1-methylimidazole complex catalyzed Mizoroki–Heck reaction of aryl chlorides with styrenes

• Ting-Ting Gao,
• Ai-Ping Jin and
• Li-Xiong Shao

Beilstein J. Org. Chem. 2012, 8, 1916–1919, doi:10.3762/bjoc.8.222

• phosphine ligands, which can then increase the catalytic activity of the metal centre and the stability of the NHC–metal complexes, have attracted growing attention in the metal-catalyzed carbon–carbon and carbon–heteroatom bond-formation reactions during the past two decades [10][11][12][13][14][15

New efficient ligand for sub-mol % copper-catalyzed C–N cross-coupling reactions running under air

• Per-Fredrik Larsson,
• Peter Astvik and
• Per-Ola Norrby

Beilstein J. Org. Chem. 2012, 8, 1909–1915, doi:10.3762/bjoc.8.221

• ; ligands; Introduction Copper-catalyzed heteroatom cross-coupling reactions (C–N, C–O and C–S) are important synthetic tools in modern organic synthesis [1][2][3][4][5][6]. Even though copper salts have been known to catalyze these transformations for a long period of time (i.e., the Ullmann [7] and

Alkenes from β-lithiooxyphosphonium ylides generated by trapping α-lithiated terminal epoxides with triphenylphosphine

• David. M. Hodgson and
• Rosanne S. D. Persaud

Beilstein J. Org. Chem. 2012, 8, 1896–1900, doi:10.3762/bjoc.8.219

• epoxides 8 by using hindered lithium amides, such as lithium tetramethylpiperidide (9, LTMP) [20], and have shown synthetically useful carbene reactivity (e.g., cyclopropanation [21][22], dimerization [23][24][25]). The reaction of carbenes and carbenoids with heteroatom lone pairs is a popular strategy to

Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes

• Gianluigi Broggini,
• Egle M. Beccalli,
• Andrea Fasana and
• Silvia Gazzola

Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198

• . Keywords: alkenylation; arylation; C–H functionalization; indoles; N–H functionalization; Pd catalysis; Introduction The development of mild and selective reactions for the direct conversion of carbon–hydrogen bonds into carbon–carbon and carbon–heteroatom bonds is a challenging goal in organic chemistry

Organocatalytic tandem Michael addition reactions: A powerful access to the enantioselective synthesis of functionalized chromenes, thiochromenes and 1,2-dihydroquinolines

• Chittaranjan Bhanja,
• Satyaban Jena,
• Sabita Nayak and
• Seetaram Mohapatra

Beilstein J. Org. Chem. 2012, 8, 1668–1694, doi:10.3762/bjoc.8.191

• most significant synthetic methods reported on chiral-amine-catalyzed tandem Michael conjugate addition of heteroatom-centered nucleophiles to α,β-unsaturated compounds followed by cyclization reactions for the enantioselective construction of functionalized chiral chromenes, thiochromenes and 1,2

• , organocatalytic enantioselective methodologies have gained much attention from many research groups worldwide [22][23][24][25][26][27][28][29]. In the meantime, organocatalytic tandem Michael conjugate additions of heteroatom-centered nucleophiles to α,β-unsaturated compounds appear as one of the most reliable

Extending the utility of [Pd(NHC)(cinnamyl)Cl] precatalysts: Direct arylation of heterocycles

• Anthony R. Martin,
• Anthony Chartoire,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2012, 8, 1637–1643, doi:10.3762/bjoc.8.187

• directing groups or particular catalyst selectivity [1][2][3][4][5]. Thus, heteroaromatic scaffolds, which are a common feature in biologically relevant compounds and in materials science [6][7] can be selectively arylated as the heteroatom can act as an intrinsic orientating group [8]. Despite the

Metal–ligand multiple bonds as frustrated Lewis pairs for C–H functionalization

• Matthew T. Whited

Beilstein J. Org. Chem. 2012, 8, 1554–1563, doi:10.3762/bjoc.8.177

• by initial coordination of a heteroatom to the highly electrophilic boron center, followed by interaction with the metal to give a four-membered metallacycle and oxygen-atom transfer upon cycloreversion [61]. Thus, the reactions are initiated by the electrophilicity at B rather than the nucleophilic