On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

•  19D). In carbocyclic substrates the displacement of a C–F bond or ionization with a Lewis acid is difficult, but mesylates are stable and suitable for AlMe3 activation. As already mentioned, indoles are an important class of molecules with potential antidiabetic properties since they can act as GPR40

Copper-based fluorinated reagents for the synthesis of CF₂R-containing molecules (R ≠ F)

• Louise Ruyet and
• Tatiana Besset

Beilstein J. Org. Chem. 2020, 16, 1051–1065, doi:10.3762/bjoc.16.92

• functionalization of alkyl bromides, alkyl mesylates, aryldiazonium salts [43] as well as electron-rich arenes [44] (Scheme 4). In 2015, the group of Qing investigated the oxidative difluoromethylation reaction of terminal alkynes with TMSCF2H via a copper-mediated reaction [45]. Using a stoichiometric amount of

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides

• Katarzyna Włodarczyk,
• Piotr Borowski and
• Marek Stankevič

Beilstein J. Org. Chem. 2020, 16, 88–105, doi:10.3762/bjoc.16.11

• /NEt3 mixture. Instead, the corresponding mesylates 60 and 61 were isolated as the sole products (Scheme 6). The compounds derived from ketones 12, 16, and 19 underwent elimination reactions to the β,γ-alkenylphosphine sulfides 62, 64, and 65 under these conditions. For sulfide 12, a mixture of two β

• -alkenylphosphine sulfides 62 and 63 (a mixture of E- and Z-isomer) was obtained under each reaction condition tested. Once all the compounds had been prepared, it was decided to test the reactivity of mesylates 60 and 61 in the presence of AlCl3 (Scheme 7). The reaction of these compounds with aluminum chloride

• proceeded smoothly, leading to the corresponding γ-mercaptoalkylphosphine oxides in good yields. Surprisingly, the reactivity of the mesylates 60 and 61 appeared to be completely different from the parent β-hydroxyalkylphosphine sulfides 8 and 9, which failed to undergo a rearrangement (see Table 2, entries

The cyclopropylcarbinyl route to γ-silyl carbocations

• Xavier Creary

Beilstein J. Org. Chem. 2019, 15, 1769–1780, doi:10.3762/bjoc.15.170

• Xavier Creary Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 45556, USA 10.3762/bjoc.15.170 Abstract The mesylate derivative of cis-1-hydroxymethyl-2-trimethylsilylcyclopropane has been prepared, along with a number of related mesylates and triflates with

• ? Answers to these questions were sought. Results and Discussion Phenyl-substituted systems The first compounds to be examined were the mesylates 19 and 20. These substrates were prepared as shown in Scheme 4. Irradiation of ethyl 2-diazo-2-phenylacetate (15) in vinyltrimethylsilane as solvent gave an

• and 18. Additionally, nOe studies on 17 confirm the stereochemical assignment. Conversion to mesylates 19 and 20 using mesyl chloride and triethylamine was straightforward. Mesylate 19 reacts readily in CD3CO2D at 20 °C (Table 1) to give the substituted cyclobutyl acetate 21 (92%) as the major product

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

An improved synthesis of adefovir and related analogues

• David J. Jones,
• Eileen M. O’Leary and
• Timothy P. O’Sullivan

Beilstein J. Org. Chem. 2019, 15, 801–810, doi:10.3762/bjoc.15.77

• the synthesis of acyclic nucleoside phosphonates including mesylates [42], tosylates [16][43][44] and alkyl chlorides [45][46][47][48][49][50][51]. Alkylation reactions conducted with these electrophiles generally require higher temperatures. Furthermore, these reagents typically afford products in

First synthesis of cryptands with sucrose scaffold

• Patrycja Sokołowska,
• Michał Kowalski and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2019, 15, 210–217, doi:10.3762/bjoc.15.20

• substantial problems. We decided, therefore, to prepare sucrose cryptands according to route b, i.e., to connect all three terminal positions at the same time. The first attempt was, however, unsuccessful. Activation of all terminal hydroxy groups as mesylates and subsequent reaction of such intermediate 14

• two carbon atoms at the C-1’ position as well as at other terminal positions. Thus, all three hydroxy groups were protected as allyl ethers which were subsequently converted into -CH2CH2OH units (Scheme 3). Activation of the free OH groups in 18 as mesylates 19 and subsequent reaction with tripodal

First DMAP-mediated direct conversion of Morita–Baylis–Hillman alcohols into γ-ketoallylphosphonates: Synthesis of γ-aminoallylphosphonates

• Marwa Ayadi,
• Haitham Elleuch,
• Emmanuel Vrancken and
• Farhat Rezgui

Beilstein J. Org. Chem. 2016, 12, 2906–2915, doi:10.3762/bjoc.12.290

• step protocol involves firstly the mesylation of corresponding alcohols and then the conversion of the intermediate mesylates into their halides. Further an Arbuzov reaction of alkyl phosphites with such halides affords the phosphonates. Interestingly, a direct conversion of common allyl alcohols into

A versatile and efficient approach for the synthesis of chiral 1,3-nitroamines and 1,3-diamines via conjugate addition to new (S,E)-γ-aminated nitroalkenes derived from L-α-amino acids

• Vera Lúcia Patrocinio Pereira,
• André Luiz da Silva Moura,
• Daniel Pais Pires Vieira,
• Leandro Lara de Carvalho,
• Eliz Regina Bueno Torres and
• Jeronimo da Silva Costa

Beilstein J. Org. Chem. 2013, 9, 832–837, doi:10.3762/bjoc.9.95

• transformation into the corresponding mesylates was followed by smooth elimination at −78 °C, leading to the desired nitroalkenes 2a–c in 95–99% yield, as single E-diastereoisomers. It is worth mentioning that the nitroalkenes 2a–c are obtained in high chemical and stereochemical purity and can be stored in a

Easy and direct conversion of tosylates and mesylates into nitroalkanes

• Alessandro Palmieri,
• Serena Gabrielli and
• Roberto Ballini

Beilstein J. Org. Chem. 2013, 9, 533–536, doi:10.3762/bjoc.9.58

• Alessandro Palmieri Serena Gabrielli Roberto Ballini “Green Chemistry Group”, School of Science and Technology, Chemistry Division, University of Camerino, Via S. Agostino 1, 62032 Camerino (MC), Italy 10.3762/bjoc.9.58 Abstract Tosylates and mesylates were directly converted into the

• corresponding nitroalkanes, by their treatment with tetrabutylammonium nitrite (TBAN) under mild conditions. Keywords: mesylates; nitroalkanes; nucleophilic substitution; tetrabutylammonium nitrite; tosylates; Introduction Nitroalkanes have proven to be one of the most valuable, versatile classes of

• source for nitroalkanes, have unsuccessful been explored in the past [28]. In fact, the conversion of alcohols into nitroalkanes requires a three-step sequence, as reported in Figure 1, that necessitates [29][30][31][32][33] (i) conversion of alcohols a into their tosylates or mesylates b, (ii

Approaches to α-amino acids via rearrangement to electron-deficient nitrogen: Beckmann and Hofmann rearrangements of appropriate carboxyl-protected substrates

• Sosale Chandrasekhar and
• V. Mohana Rao

Beilstein J. Org. Chem. 2012, 8, 1393–1399, doi:10.3762/bjoc.8.161

• ), their carboxyl groups being masked as a 2,4,10-trioxaadamantane unit (an orthoacetate). The oxime mesylates have been rearranged with basic Al2O3 in refluxing CHCl3, and the malonamic acids with phenyliodoso acetate and KOH/MeOH. Both routes are characterized by excellent overall yields. Structure

• MeSO2Cl (1.5 mmol). The mixtures were stirred for 2 h and washed with water, etc. The crude mixtures were purified by column chromatography on grade 1 neutral alumina to obtain 4. Beckmann rearrangement of 4 to final amides 5 [17]. Mesylates 4 (1.0 mmol) in CHCl3 (5.0 mL) were treated with basic alumina

Expanding the chemical diversity of spirooxindoles via alkylative pyridine dearomatization

• Chunhui Dai,
• Bo Liang and
• Corey R. J. Stephenson

Beilstein J. Org. Chem. 2012, 8, 986–993, doi:10.3762/bjoc.8.111

• coupling, whereupon methanesulfonyl chloride was added slowly over a 1 h period at 0 °C and another 2 h at the same temperature to trap the vinylogous acid as vinyl mesylates 6. Various N-substituted isatins and 1,3-dicarbonyl compounds were then explored and the results are presented in Table 1. Beginning

Recent advances in direct C–H arylation: Methodology, selectivity and mechanism in oxazole series

• Cécile Verrier,
• Pierrik Lassalas,
• Laure Théveau,
• Guy Quéguiner,
• François Trécourt,
• Francis Marsais and
• Christophe Hoarau

Beilstein J. Org. Chem. 2011, 7, 1584–1601, doi:10.3762/bjoc.7.187

• , tosylates, mesylates and phosphonates. Research efforts in this field are now focused on mechanism considerations since the broad diversity of catalytic metalation pathways represents undoubtedly an attractive tool for regioselectivity and the development of novel methodologies. Up until very recently

• calculations on oxazole-4-carboxylate; (b) Developed novel CMD direct arylation methodologies. aTS CMD Free Gibbs energy; bHOMO coefficient; cpartial charge (ESP). Pd(0)-catalyzed direct arylation of (benz)oxazoles with tosylates and mesylates [71]. Pd(0)-catalyzed direct arylation of oxazoles with sulfamates

Efficient syntheses of 25,26-dihydrodictyostatin and 25,26-dihydro-6-epi-dictyostatin, two potent new microtubule-stabilizing agents

• María Jiménez,
• Wei Zhu,
• Andreas Vogt,
• Billy W. Day and
• Dennis P. Curran

Beilstein J. Org. Chem. 2011, 7, 1372–1378, doi:10.3762/bjoc.7.161

• mesylate 14 [36] gave alcohol 15 in 77% yield. Interestingly, the Marshall reaction works well even with mesylates containing a terminal alkyne; reaction of 13 with 16 provided 17 in 72% yield. The TIPS and primary TBS groups of 15 were simultaneously cleaved under basic conditions with TBAF [37] (88

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

• -functionalized ketones were isolated in useful yields. Besides linear allenes, exocyclic allenes such as 1j and 1k were also suitable substrates and gave mesylates 2j and 2k in 72% and 59% yield, respectively (entries 9 and 10). Some substrates, however, did not participate in this reaction effectively. For

Understanding the mechanism of Pd-catalyzed allylic substitution of the cyclic difluorinated carbonates

• Jun Xu,
• Xiao-Long Qiu and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2008, 4, No. 18, doi:10.3762/bjoc.4.18

• fluoroalkyl groups would alter the regioselectivities of acyclic allylic alkylation compared with their non-fluorinated counterparts [12][13][14][15][16][17], their reactions mostly concerned the Pd-catalyzed regio- and stereoselective formate reduction of fluorine-containing allylic mesylates. To the best of

Diastereoselective synthesis of some novel benzopyranopyridine derivatives

• Pradeep K. Mohakhud,
• Sujeet M. R. Kumar,
• Vasanth M. R. Kumar,
• Ravi M. R. Kumar,
• Moses D. R. Babu,
• Vyas D. R. K and
• Om D. R. Reddy

Beilstein J. Org. Chem. 2006, 2, No. 25, doi:10.1186/1860-5397-2-25

• methanesulfonylchloride, in the presence of base, which provided the required 3-mesylate derivatives 3a and 3b. Mesylates 3a and 3b were condensed with 3,4-methylenedioxyphenol in the presence of base and solvent to give ethers 4a and 4b. These ethers, on treatment with acid, underwent unexpected cyclization to give rise

Do α-acyloxy and α-alkoxycarbonyloxy radicals fragment to form acyl and alkoxycarbonyl radicals?

• Dennis P. Curran and
• Tiffany R. Turner

Beilstein J. Org. Chem. 2006, 2, No. 10, doi:10.1186/1860-5397-2-10

• through mesylates by a standard procedure. Iodides 11a and 11b were stable to heating at 120°C in C6D6 for 24 h, so polar pathways for product formation are not likely in the cyclization experiments described below. The projected mechanism for cyclizations of 11a,b with Bu3SnH in a competition kinetics

Synthesis of 2,6-trans- disubstituted 5,6-dihydropyrans from (Z)-1,5-syn-endiols

• Eric M. Flamme and
• William R. Roush

Beilstein J. Org. Chem. 2005, 1, No. 7, doi:10.1186/1860-5397-1-7

• the cyclodehydration reactions of diol substrates were complicated by selectivity and reactivity issues (Figure 1 and Figure 2), we turned to an alternative strategy which would not rely on chemoselectivity in the cyclodehydration step. To this end, mesylates 11 were synthesized (Scheme 3). Treatment

• deprotection of the TBS ether by using 3HFEt3N afforded mesylates 11 (80 – ≥ 95% yield). Treatment of mesylate 11a with 1 equivalent of potassium tert-butoxide in tert-BuOH (0.01 M) between 40–50 °C provided ent-3a in 75% yield and 10:1 selectivity for the dihydropyran product and a diene resulting from an

• temperatures. However, a much more general procedure for synthesis of the enantiomeric dihydropyrans ent-3 involves the stannyl ether mediated cyclization of hydroxy mesylates 11. This method relies on a selective silylation of the homoallylic alcohol, and represents a new route to access 2,6-trans