Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

• Robin Klintworth,
• Garreth L. Morgans,
• Stefania M. Scalzullo,
• Charles B. de Koning,
• Willem A. L. van Otterlo and
• Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

• well as tert-butyl as precursors for the silica gel-mediated cyclization reaction to form pyrrolizine products. The bromomethyl ketones required for the initial sulfide contraction were either purchased from commercial suppliers or prepared from the corresponding methyl ketones by reported procedures

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• radical source via a nickel/photoredox-catalyzed HAT processes (Scheme 28) [92]. The method was also compatible with other chlorine-containing electrophiles such as acyl chlorides 45 to afford methyl ketones 47 in moderate yields. Based on the detailed mechanistic studies, the authors proposed a catalytic

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• the Grignard reagent in this synthesis, with a 18% overall yield after seven steps from aldimine ent-126 (Scheme 35) [125]. The reaction of chiral α-siloxyl imine (SS)-126 with enolates derived from methyl ketones 131 was also investigated. The enolate was formed with LDA at −78 °C and reacted at the

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• +) species, secondly as a weak base to neutralize HI and next to reoxidize the iodide ion (I−) to molecular iodine (I2, Scheme 33). The reaction has enjoyed a broad substrate scope including arylmethyl, heteroaryl, α,β-unsaturated methyl ketones, β-ketone esters and 2-APs-substituted with EW and EDGs. The

• . Substituted aryl ketones, heteroaryl methyl ketones, and α,β-unsaturated methyl ketones were also well tolerated by the reaction (Scheme 44). The reaction was also successful in a two-step procedure in which the product of 2-AP and ketone can also be subjected to cyanation with benzyl cyanide thereby proving

Synthesis, effect of substituents on the regiochemistry and equilibrium studies of tetrazolo[1,5-a]pyrimidine/2-azidopyrimidines

• Elisandra Scapin,
• Paulo R. S. Salbego,
• Caroline R. Bender,
• Alexandre R. Meyer,
• Anderson B. Pagliari,
• Tainára Orlando,
• Geórgia C. Zimmer,
• Clarissa P. Frizzo,
• Helio G. Bonacorso,
• Nilo Zanatta and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 2396–2407, doi:10.3762/bjoc.13.237

• procedure for the synthesis of β-enaminones 1a–i β-Enaminones 1a–i were prepared from the reaction of N,N-dimethylformamide dimethylacetal with methyl ketones in accordance with the methodology developed in our laboratory [31]. General procedure for the synthesis of tetrazolo[1,5-a]pyrimidines 3a–g, 4a–g

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• adduct 214, resulting from condensation of aldehydes 211 and nitrile derivatives 212, lead to cyclo-adduct intermediates 216 which cyclize to phosphorylated pyrazoles 217. In this way, a one-pot three-component reaction of aldehydes 218, methyl ketones 219 and the Bestmann–Ohira reagent has been

Iodine-mediated synthesis of 3-acylbenzothiadiazine 1,1-dioxides

• Long-Yi Xi,
• Ruo-Yi Zhang,
• Lei Shi,
• Shan-Yong Chen and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2016, 12, 1072–1078, doi:10.3762/bjoc.12.101

• benzothiadiazine 1,1-dioxides. Besides acetophenones, heteroaryl methyl ketones also underwent this transformation, affording the corresponding products in moderate yields (3n and 3o). When 1-(naphthalen-2-yl)ethanone was subjected to this reaction, a good yield of the desired product 3p was isolated. To widen the

Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen

• Hans Sterckx,
• Johan De Houwer,
• Carl Mensch,
• Wouter Herrebout,
• Kourosch Abbaspour Tehrani and
• Bert U. W. Maes

Beilstein J. Org. Chem. 2016, 12, 144–153, doi:10.3762/bjoc.12.16

• anilines resulting in the formation of 2-aryl-α-ketoacetamides was reported by Jiao [22] and a closely related intramolecular variant leading to isatins has been published by Ilangovan [23]. A remarkable Cu-catalyzed chemoselective oxidative C–C bond cleavage of methyl ketones was reported by the group of

• Liu and Bi [24]. This useful transformation makes use of CuI/O2 in DMSO to convert methyl ketones into aldehydes in a sustainable manner. Recently our group reported a synthetic protocol for the copper- and iron-catalyzed aerobic oxidation of the methylene group of aryl(di)azinylmethanes using acetic

A new and convenient synthetic way to 2-substituted thieno[2,3-b]indoles

• Roman A. Irgashev,
• Arseny A. Karmatsky,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2015, 11, 1000–1007, doi:10.3762/bjoc.11.112

• –Knorr cyclization, thus affording tricyclic thieno[2,3-b]indoles. Keywords: aldol-crotonic condensation; isatin; Lawesson’s reagent; methyl ketones; Paal–Knorr reaction; thieno[2,3-b]indole; Introduction 8H-Thieno[2,3-b]indole is a fused heterocyclic system, which has attracted a considerable

• corresponding acetylated (hetero)arenes which are easily accessible reagents, including commercially available ones. It is well known that the reaction of isatins 7 with methyl ketones 8 leads to the formation of aldol-type adducts 9 under catalysis with mild bases, such as secondary or tertiary amines. These

• indoline-2-ones 11 from isatins and methyl ketones has previously been realized [32][33]. In particular, preparation of 2-methyl-8H-thieno[2,3-b]indole from unsubstituted isatin and acetone in 15% yield has been reported [32] (Scheme 2). Although it seems to be a very harmonious strategy, it has hardly a

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• methyl ketones occurs when using water instead of sodium acetate and acetic acid, all other conditions being the same [221]. The coupling of terminal alkenes 237 with carboxylic acids having complex structures 238 resulted in the selective formation of linear E-allyl esters 239 (Scheme 50) [222]. These

Asymmetric organocatalytic decarboxylative Mannich reaction using β-keto acids: A new protocol for the synthesis of chiral β-amino ketones

• Chunhui Jiang,
• Fangrui Zhong and
• Yixin Lu

Beilstein J. Org. Chem. 2012, 8, 1279–1283, doi:10.3762/bjoc.8.144

• ketones. Application of aryl methyl ketones in the asymmetric Mannich reaction by enamine catalysis remains elusive. On the other hand, the only chiral Brønsted acid catalytic system based on BINOL-phosphates was reported by Rueping et al. Unfortunately, the yields of the reported reactions were

• aryl methyl ketones, we wondered whether β-keto acids could serve as an enolate equivalent to aryl methyl ketones upon decarboxylation (Scheme 1). The proposed addition–decarboxylation sequence is consistent with current mechanistic understanding [31][35][37][38]. However, we cannot exclude an

Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10

• Teresa Weise,
• Marco Kai,
• Anja Gummesson,
• Armin Troeger,
• Stephan von Reuß,
• Silvia Piepenborn,
• Francine Kosterka,
• Martin Sklorz,
• Ralf Zimmermann,
• Wittko Francke and
• Birgit Piechulla

Beilstein J. Org. Chem. 2012, 8, 579–596, doi:10.3762/bjoc.8.65

• observed. As an example, in PTR–MS analyses the signal at m/z = 109 is about as intensive as those produced by the methyl ketones at m/z = 157, m/z = 171, and m/z = 185 (Figure 4A). In contrast, in our GC/MS analyses the sum of 2,5-dimethylpyrazine (8) and benzylalcohol (18) (Figure 2, Table 1), which may

• commercially available or specifically synthesized reference compounds (co-injection). Synthetic 10-methylundecan-2-one and 9-methylundecan-2-one served as standards for the structure assignments of other branched-chain methyl ketones on the basis of their mass spectra and retention indices. Cultivation on

Novel fatty acid methyl esters from the actinomycete Micromonospora aurantiaca

• Jeroen S. Dickschat,
• Hilke Bruns and
• Ramona Riclea

Beilstein J. Org. Chem. 2011, 7, 1697–1712, doi:10.3762/bjoc.7.200

• compounds and methyl ketones, more than half of the components identified are unbranched and mono- and dimethylbranched FAMEs, many of this last group having not been reported before. Results and Discussion Volatiles from Micromonospora aurantiaca The volatiles released by agar plate cultures of the

Continuous-flow hydration–condensation reaction: Synthesis of α,β-unsaturated ketones from alkynes and aldehydes by using a heterogeneous solid acid catalyst

• Magnus Rueping,
• Teerawut Bootwicha,
• Hannah Baars and
• Erli Sugiono

Beilstein J. Org. Chem. 2011, 7, 1680–1687, doi:10.3762/bjoc.7.198

• batch reactions in particular with regard to the continuous harvesting of the product, the fast optimization of the reaction parameters, the simple operation and reliability, and the restriction of byproduct formation, especially the formation of methyl ketones and propargylic alcohols. Experimental

Gold-catalyzed regioselective oxidation of terminal allenes: formation of α-methanesulfonyloxy methyl ketones

• Yingdong Luo,
• Guozhu Zhang,
• Erik S. Hwang,
• Thomas A. Wilcoxon and
• Liming Zhang

Beilstein J. Org. Chem. 2011, 7, 596–600, doi:10.3762/bjoc.7.69

• Yingdong Luo Guozhu Zhang Erik S. Hwang Thomas A. Wilcoxon Liming Zhang Department of Chemistry and Biochemistry, University of California, Santa Barbara, California, 93106, USA 10.3762/bjoc.7.69 Abstract Synthetically useful α-methanesulfonyloxy methyl ketones are readily prepared in one-step

• synthesis of α-methanesulfonyloxy methyl ketones. Results and Discussion Initially, trideca-1,2-diene (1a) was treated with commercially available pyridine N-oxide in the presence of MsOH (5 equiv) and Ph3PAuNTf2 (5 mol %) in DCE at room temperature. Consumption of 1a was initially observed and was complete

• first gold-catalyzed intermolecular oxidation of allenes. With 3,5-dichloropyridine N-oxide as the oxidant and in the presence of MsOH, α-methanesulfonyloxy methyl ketones are formed in one step in fair to good yield with excellent regioselectivities under relatively mild reaction conditions. The

Highly substituted benzannulated cyclooctanol derivatives by samarium diiodide-induced cyclizations

• Jakub Saadi,
• Irene Brüdgam and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2010, 6, 1229–1245, doi:10.3762/bjoc.6.141

• cyclohexanone derived γ-ketoesters F preferred the 7-exo-trig over the 8-endo-trig-cyclization mode (Scheme 16). A typical side reaction, which was observed for methyl ketones or cyclohexanone derivatives, was the ketyl-aryl coupling reaction leading to hexahydronaphthalene derivatives in low yields. In

The role of an aromatic group in remote chiral induction during conjugate addition of α-sulfonylallylic carbanions to ethyl crotonate

• Shlomo Levinger,
• Ranjeet Nair and
• Alfred Hassner

Beilstein J. Org. Chem. 2008, 4, No. 32, doi:10.3762/bjoc.4.32

• -(2-thienyl)ethanamine (6d) was prepared from 2-acetylthiophene 7d by a modified Leuckart reaction [5][6], while amines 6b, 6f, 6g and 6i were obtained through Borch reductive amination of the corresponding methyl ketones 7 with sodium cyanoborohydride and ammonium acetate in methanol (Scheme 3) [7][8