Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

• Warner have proposed 12 Principles of Green Chemistry as a guide to help making chemical processes more environmentally friendly [13][14]. Many of the requirements contained in these principles (e.g., prevention, atom economy, energy efficiency, catalysis, safe synthesis) can be met if the reactions are

Encaging palladium(0) in layered double hydroxide: A sustainable catalyst for solvent-free and ligand-free Heck reaction in a ball mill

• Wei Shi,
• Jingbo Yu,
• Zhijiang Jiang,
• Qiaoling Shao and
• Weike Su

Beilstein J. Org. Chem. 2017, 13, 1661–1668, doi:10.3762/bjoc.13.160

• such as Heck, Suzuki, Sonogashira and Glaser reactions are still unusual methods for the formation of C–C bonds [1][2][3][4][5][6][7], but the method arouse considerable attention because of an environmentally benign and solvent-free synthesis approach as well as high efficiency and good atom economy

Construction of highly enantioenriched spirocyclopentaneoxindoles containing four consecutive stereocenters via thiourea-catalyzed asymmetric Michael–Henry cascade reactions

• Yonglei Du,
• Jian Li,
• Kerong Chen,
• Chenglin Wu,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2017, 13, 1342–1349, doi:10.3762/bjoc.13.131

• simple 3-substituted oxindoles and nitrovinylacetamide as starting materials was achieved successfully. This protocol features operational simplicity, high atom economy, and high catalytic asymmetry, thus representing a versatile approach to the synthesis of highly enantioenriched

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

• M. Fernanda N. N. Carvalho,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

• platinum(II). The formed product structures depend not only on the reagents used but also on the substituents attached to the triple bonds. Cycloisomerisations with perfect atom economy lead to polycyclic heterocycles that resemble to some extent the AB ring system of paclitaxel. Herein, we present

• the C–C bond between the atoms bearing the OH and NH groups (ring enlargement). The result is an isomerisation of 4a and 4b to form tricyclic compounds 7 containing a nine-membered carbocyclic ring (Scheme 3a) [27]. Isomerisations are the best examples for a perfect “atom economy” [28][29][30] since

N-Propargylamines: versatile building blocks in the construction of thiazole cores

• S. Arshadi,
• E. Vessally,
• L. Edjlali,
• R. Hosseinzadeh-Khanmiri and
• E. Ghorbani-Kalhor

Beilstein J. Org. Chem. 2017, 13, 625–638, doi:10.3762/bjoc.13.61

• the literature. In this review we discussed the most representative and interesting reports on this emerging field. As illustrated, the processes provided the title compounds in good yields with fewer steps and higher atom economy than previously reported examples. We hope that this review will

Effect of the ortho-hydroxy group of salicylaldehyde in the A³ coupling reaction: A metal-catalyst-free synthesis of propargylamine

• Sujit Ghosh,
• Kinkar Biswas,
• Suchandra Bhattacharya,
• Pranab Ghosh and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 552–557, doi:10.3762/bjoc.13.53

• only metal-catalyst-free approach from acetylene carboxylic acids that are difficultly accessible and with low atom economy. Thus the present reaction from easily available A3 components leading to the formation of propargylamine under metal-catalyst-free and solvent-free conditions could attract the

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

• Flavio Fanelli,
• Giovanna Parisi,
• Leonardo Degennaro and
• Renzo Luisi

Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51

• becoming a new technique for fulfilling several of the twelve green chemistry principles. The microreactor approach, could provide protection, preserves atom economy, guarantees less hazardous chemical synthesis and allows the use of safer solvents and auxiliaries. Furthermore, it pushes towards designing

• organic synthesis, very recent examples have been selected and will be discussed here. In the context of green chemistry [11], protecting-group free organic synthesis has received particular attention in the last years, because of atom economy [12][13][14][15] and reduction of synthetic steps [16]. It has

Synthesis of structurally diverse 3,4-dihydropyrimidin-2(1H)-ones via sequential Biginelli and Passerini reactions

• Andreas C. Boukis,
• Baptiste Monney and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2017, 13, 54–62, doi:10.3762/bjoc.13.7

• precursor components. MCRs are often one-pot reactions with high-atom economy, convergence and efficiency. Generally, one-pot procedures have many advantages compared to multiple-step syntheses [1][2][3]. One-pot MCRs can shorten reaction times, provide high yields, reduce work-up steps and waste as well as

cis-Diastereoselective synthesis of chroman-fused tetralins as B-ring-modified analogues of brazilin

• Dimpee Gogoi,
• Runjun Devi,
• Pallab Pahari,
• Bipul Sarma and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2016, 12, 2816–2822, doi:10.3762/bjoc.12.280

• the synthesis of carbo- and heterocyclic compounds [21][22][23][24]. The easy accessibility of racemic and enantiomerically pure epoxy substrates through a number of well-established epoxidation methods coupled with procedural simplicity, high atom economy, regio- and stereoselectivity of IFCEA

Copper-catalyzed asymmetric sp³ C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst

• Pierre Querard,
• Inna Perepichka,
• Eli Zysman-Colman and
• Chao-Jun Li

Beilstein J. Org. Chem. 2016, 12, 2636–2643, doi:10.3762/bjoc.12.260

• interest in terms of atom economy, nevertheless enantioselectivity is difficult to control due to often-required harsh reaction conditions. Therefore, the development of simple and facile processes to functionalize sp3 C–H bonds under mild conditions in the absence of directing groups is of great interest

Catalytic Wittig and aza-Wittig reactions

• Zhiqi Lao and
• Patrick H. Toy

Beilstein J. Org. Chem. 2016, 12, 2577–2587, doi:10.3762/bjoc.12.253

• large scale, in the context of green sustainable chemistry. For example, it has low atom economy due to its requirement of one molar equivalent of a phosphine reagent, and the formation of a corresponding amount of a phosphine oxide, usually Ph3P=O (2). There is also the associated problem of separating

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

• Donghui Pan,
• Yanbin Wang and
• Guomin Xiao

Beilstein J. Org. Chem. 2016, 12, 2443–2449, doi:10.3762/bjoc.12.237

• the selectivity and allows for the complete utilization of bromine atoms, thus increasing the atom economy [16]. These advantages prompted us to develop a novel method to prepare 1-(bromomethyl)-2,5-dichloro-4-methylbenzene and 4,7,12,15-tetrachloro[2.2]paracyclophane in a convenient and green way

A new paradigm for designing ring construction strategies for green organic synthesis: implications for the discovery of multicomponent reactions to build molecules containing a single ring

• John Andraos

Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236

• starting materials to the final desired products. Recently, a measure of the associated probability of achieving reaction intrinsic “greenness” based on simple reaction yield (RY) and atom economy (AE) threshold constraints was advanced [9]. That work demonstrated that both of these metrics, which define

• “intrinsic greenness”, were critical in influencing whether or not chemical reactions could achieve a minimum standard of overall greenness, regardless of how much auxiliary material (solvents, etc.) was used. Optimization toward overall greenness was best achieved by first maximizing atom economy and

• considered as precursors to the desired ring product structure. This allows the attainment of an elite list of “green” options for synthesizing a given target ring structure that satisfies the criteria of “intrinsic” greenness as defined by the inequality conditions imposed on the key metrics atom economy

The weight of flash chromatography: A tool to predict its mass intensity from thin-layer chromatography

• Freddy Pessel,
• Jacques Augé,
• Isabelle Billault and
• Marie-Christine Scherrmann

Beilstein J. Org. Chem. 2016, 12, 2351–2357, doi:10.3762/bjoc.12.228

• sequences from the global material economy GME (Equation 4), which is related to the atom economy, the yields of each step, the excess of reactants and the mass of auxiliaries [6][7]. It can be fractioned into three parts: reaction itself (MIR), work-up (MIW) and purification (MIP) as shown by Equation 5 [8

Tunable microwave-assisted method for the solvent-free and catalyst-free peracetylation of natural products

• Manuela Oliverio,
• Paola Costanzo,
• Monica Nardi,
• Carla Calandruccio,
• Raffaele Salerno and
• Antonio Procopio

Beilstein J. Org. Chem. 2016, 12, 2222–2233, doi:10.3762/bjoc.12.214

• di-glycosylated derivative of quercetin (13), demonstrated that an additional acetylation run could give rise also to a quercetin peracetylation. An evaluation of the greenness of the process was performed by calculation of atom economy (AE), reaction mass efficiency (RME), mass intensity (MI) and

Diels–Alder reactions in confined spaces: the influence of catalyst structure and the nature of active sites for the retro-Diels–Alder reaction

• Ángel Cantín,
• M. Victoria Gomez and
• Antonio de la Hoz

Beilstein J. Org. Chem. 2016, 12, 2181–2188, doi:10.3762/bjoc.12.208

• selectivity and atom economy. Moreover, Diels–Alder cycloadditions in combination with heterogeneous catalysts (i.e. doped-microporous materials) represent an interesting approach for the conversion of biomass feedstock into stable chemicals such as furfural derivatives, platform molecules which can be

The in situ generation and reactive quench of diazonium compounds in the synthesis of azo compounds in microreactors

• Faith M. Akwi and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 1987–2004, doi:10.3762/bjoc.12.186

• principles of green chemistry [1][2] such as less hazardous chemical synthesis, efficient atom economy, reduction of waste produced, some alternative cleaner methods for the synthesis of azo dyes have been developed. These methods are however only representative of particular coupling agents and diazotized

• undesirable side reaction, thus increasing the atom economy in the reaction. This in turn reduces the amount of waste generated after the reaction. A reaction conversion of almost 100% was attained in 2.3 seconds. The same reaction performed at a macro scale and at a strong stirring rate providing a

Catalytic Chan–Lam coupling using a ‘tube-in-tube’ reactor to deliver molecular oxygen as an oxidant

• Carl J. Mallia,
• Paul M. Burton,
• Alexander M. R. Smith,
• Gary C. Walter and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2016, 12, 1598–1607, doi:10.3762/bjoc.12.156

• protocols it is clear that the use of sub-stoichiometric amounts of the copper catalysts presents an advantage over the stoichiometric amount used in the original flow studies [13]. Additionally, the use of oxygen as the oxidant offers improved atom economy over the use of systems such as TEMPO and tert

One-pot synthesis of tetracyclic fused imidazo[1,2-a]pyridines via a three-component reaction

• Bo Yang,
• Chuanye Tao,
• Taofeng Shao,
• Jianxian Gong and
• Chao Che

Beilstein J. Org. Chem. 2016, 12, 1487–1492, doi:10.3762/bjoc.12.145

• Multicomponent reactions (MCRs) have attracted considerable attention in organic and medicinal chemistry due to their high efficiency, simple operability, atom economy and unmatched versatility [1][2][3][4][5][6]. Especially, these reactions serve as an ideal synthetic tool for the assembly of structurally

Development of chiral metal amides as highly reactive catalysts for asymmetric [3 + 2] cycloadditions

• Yasuhiro Yamashita,
• Susumu Yoshimoto,
• Mark J. Dutton and
• Shū Kobayashi

Beilstein J. Org. Chem. 2016, 12, 1447–1452, doi:10.3762/bjoc.12.140

• biologically active compounds are particularly important. Chiral Lewis acid/Brønsted base-catalyzed carbon–carbon bond-forming reactions are one of the most efficient methods from the viewpoint of atom economy because only proton transfer occurs between starting materials and target products [2]. Several kinds

A quadruple cascade protocol for the one-pot synthesis of fully-substituted hexahydroisoindolinones from simple substrates

• Hong-Bo Zhang,
• Yong-Chun Luo,
• Xiu-Qin Hu,
• Yong-Min Liang and
• Peng-Fei Xu

Beilstein J. Org. Chem. 2016, 12, 253–259, doi:10.3762/bjoc.12.27

• one-pot cascade quadruple protocol features readily available starting materials, simple manipulation, mild conditions and good atom economy. Keywords: bifunctional catalysis; hexahydroisoindolinones; one-pot synthesis; quadruple cascade; Introduction Isoindolines and their congeners are one kind of

Organocatalytic and enantioselective Michael reaction between α-nitroesters and nitroalkenes. Syn/anti-selectivity control using catalysts with the same absolute backbone chirality

• Jose I. Martínez,
• Uxue Uria,
• Maria Muñiz,
• Efraím Reyes,
• Luisa Carrillo and
• Jose L. Vicario

Beilstein J. Org. Chem. 2015, 11, 2577–2583, doi:10.3762/bjoc.11.277

• arises as a key methodology for chemical production of enantiomerically enriched chiral compounds in terms of atom economy and reduced waste generation [2][3][4][5][6]. Nowadays, many very effective methodologies exist that allow the formation of a chiral compound as a single enantiomer. However, and

Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

• A. John Blacker and
• Katherine E. Jolley

Beilstein J. Org. Chem. 2015, 11, 2408–2417, doi:10.3762/bjoc.11.262

• added to reactions [3][17], however, it has a low atom economy, poor economics, and requires separation of the succinimide byproduct [18]. The tert-butyl hypochlorite (t-BuOCl) reagent is also used regularly, but is similarly expensive, wasteful and hazardous [14][19][20][21]. On the other hand sodium

• literature batch procedures. The atom economy of our process was increased compared to the use of N-chlorosuccinimide [3], or NaOCl/t-BuOH, Table 3, entries 2 and 3 [20]. There are also improvements to the total mass intensity of the flow procedure, primarily by avoiding work-up and purification procedures

Profluorescent substrates for the screening of olefin metathesis catalysts

• Raphael Reuter and
• Thomas R. Ward

Beilstein J. Org. Chem. 2015, 11, 1886–1892, doi:10.3762/bjoc.11.203

• functional groups and its atom economy [4]. Chemists treasure its extraordinary versatility. From the production of polymers [5][6] and petrochemicals to the synthesis of complex natural products [7], olefin metathesis has been established as a useful tool for solving numerous synthetic challenges. In more

Influence of bulky yet flexible N-heterocyclic carbene ligands in gold catalysis

• Alba Collado,
• Scott R. Patrick,
• Danila Gasperini,
• Sebastien Meiries and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 1809–1814, doi:10.3762/bjoc.11.196

• atom economy. A number of gold complexes have been shown to be active in this transformation [51][52][53][54][55][56][57][58]. Much effort has been devoted to the development of more sustainable gold-promoted protocols and several advances have been made in this field, e.g., very low catalyst loadings

• be efficient catalysts in this transformation [52][59][60] which proceeds with 100% atom economy. In addition, previous findings showed that the digold complex, [{Au(NHC)}2(μ-OH)][BF4], bearing IPent was more efficient than the IPr analogue in this reaction [52]. This result encouraged us to test the