[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• , dimethoxymethanofullerene 7, was obtained by Diederich and Isaacs according to Scheme 6 [83]: It was demonstrated that electron-withdrawing diazoacetates 8–10 and symmetric diazomalonates 11 and 12 can be involved in the reaction with C60 to give the corresponding methanofullerenes (Scheme 7) [77][83][84]. Later, the C60

Copper-promoted/copper-catalyzed trifluoromethylselenolation reactions

• Clément Ghiazza and
• Anis Tlili

Beilstein J. Org. Chem. 2020, 16, 305–316, doi:10.3762/bjoc.16.30

• trifluoromethylselenolated alkyne product could be isolated. After that, the same group studied the α-trifluoromethylselenolation of ketones and esters starting from the corresponding halides or diazoacetates (Scheme 4) [19][20]. Both methods led to the desired products with moderate to very good yields, and the reactions

• were performed at temperatures between 40–45 °C. Interestingly, a tertiary α-bromoketone furnished the product in 66% yield, excluding an SN2 mechanism. However, it is worth mentioning that diazoacetates bearing pyridine motifs were not suitable to be used under these conditions. Following this, the

• . Trifluoromethylselenolation of diazoacetates and diazonium salts with Me4NSeCF3 by the group of Goossen. Trifluoromethylselenolation with ClSeCF3 by the group of Tlili and Billard. Trifluoromethylselenolation with TsSeCF3 by the group of Tlili and Billard. Copper-catalyzed synthesis of a selenylated analog 30 of Pretomanid

Reusable and highly enantioselective water-soluble Ru(II)-Amm-Pheox catalyst for intramolecular cyclopropanation of diazo compounds

• Hamada S. A. Mandour,
• Yoko Nakagawa,
• Masaya Tone,
• Hayato Inoue,
• Nansalmaa Otog,
• Ikuhide Fujisawa,
• Soda Chanthamath and
• Seiji Iwasa

Beilstein J. Org. Chem. 2019, 15, 357–363, doi:10.3762/bjoc.15.31

• previous work, we developed Ru(II)-Pheox catalysts for the intramolecular cyclopropanation of trans-allylic diazoacetates in a biphasic medium [29][30][31]. During the course of our continuous study on the development of a series of Ru(II)-Pheox catalysts, we found the introduction of an ammonium group on

• intramolecular cyclopropanation of a variety of diazo compounds such as diazoacetates and diazoacetamides in a biphasic medium. Diazoacetates were tested in our catalytic system because they are widely used for intramolecular cyclopropanation reactions and also the resulted lactones are widely distributed in

• cyclopropanation using various diazo compounds with Ru(II)-Amm-Pheox Several diazoacetates and diazoacetamides were tested for asymmetric intramolecular cyclopropanation reactions using Ru(II)-Amm-Pheox catalyst (cat. 2) in H2O/ether biphasic medium as shown in Table 1. A diazo compound derived from allyl

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

• given our experience with group 11 metal-based catalysts for carbene-transfer reactions from diazoacetates [15][16], we have investigated this transformation and found that the gold complex IPrAuCl (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene) along with one equivalent of NaBArF4 (BArF4

• standard. Effect of the pressure of ethylene on the yields of ethyl cyclopropanecarboxylate in the reaction of ethylene and EDA catalyzed by IPrAuCl/NaBArF4. (a) General metal-catalyzed olefin cyclopropanation reaction with diazo compounds. (b) The ethylene cyclopropanation with diazoacetates leads to

On the cause of low thermal stability of ethyl halodiazoacetates

• Magnus Mortén,
• Martin Hennum and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2016, 12, 1590–1597, doi:10.3762/bjoc.12.155

• briefly studied the thermal, non-catalytic cyclopropanation of styrenes and compared the results to the analogous Rh(II)-catalyzed reactions. Keywords: carbenes; catalysis; cyclopropanation; halo diazoacetates; half-lives; thermal stability; Introduction The chemistry of diazo compounds has fascinated

• are usually two orders of magnitude higher and the reaction times longer in comparison to the decomposition rate of 2b. There are in principle three pathways for the thermal decomposition of the halo diazoacetates [3]: 1) a unimolecular extrusion of dinitrogen giving N2 (g) and a carbene; 2) a

• styrenes at room temperature, which are unusually mild conditions for catalyst-free cyclopropanation reactions. All together this puts the ethyl halodiazoacetates into a separate category of diazoacetates where the halodiazoacetates themselves are much more thermally unstable than EDA, while being

Enantioselective carbenoid insertion into C(sp³)–H bonds

• J. V. Santiago and
• A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

• reaction. The catalyst 17c showed opposite enantioselectivity when compared to the catalysts 17a and 17b, with the S-enantiomer formed as the major product. In 1991, Doyle and coworkers published asymmetric synthesis of lactones from alkyl diazoacetates in high enantioselectivity by intramolecular rhodium

• in C(sp3)–H bonds in a diastereo- and enantioselective manner. For enantioselective insertion reactions the authors tested two specific iridium complexes, 61a and 61b. The authors used a wide range of α-substituted α-diazoacetates for performing insertion into substrates such as tetrahydrofuran (24

• dimers of α-substituted α-diazoacetates as the main products of this reaction. This issue was circumvented when low temperatures, −50 °C, were used and the insertion reaction occurred with considerable yields and good enantiomeric excess (Table 8). According to the authors, the low temperature could

Synthesis of quinoline-3-carboxylates by a Rh(II)-catalyzed cyclopropanation-ring expansion reaction of indoles with halodiazoacetates

• Magnus Mortén,
• Martin Hennum and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2015, 11, 1944–1949, doi:10.3762/bjoc.11.210

• purification over silica gel eluting with CH2Cl2/EtOAc. Synthesis of halo diazoacetates [17]. The reaction between halodiazoacetates and indole. Proposed reaction pathway. Attempted cyclopropanation of N-Boc indole. The reaction between ethyl bromo diazoacetate and N-Me-indole. Substrate scope. Supporting

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• for an efficient reaction. Alkali metal acetates are known to facilitate decomposition of aryldiazonium salts by the formation of diazoacetates and diazo anhydrides, which decompose to aryl radicals [76]. These additives were used in Meerwein arylation of isopropenyl acetate [77]. In our case, two

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

• , and water or alcohols 38. The scope of the reaction was thoroughly investigated. Thus, methyl aryl diazoacetates and N-aryl aldimines, with electronically diverse metha or para-substituents on the aryl moieties, as well as ethyl 2-diazobutanoate gave good results, only nitro and ortho-substituted aryl

α-Bromodiazoacetamides – a new class of diazo compounds for catalyst-free, ambient temperature intramolecular C–H insertion reactions

• Åsmund Kaupang and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2013, 9, 1407–1413, doi:10.3762/bjoc.9.157

• interpreted from Table 1, the dominant reaction pathway in the high-yielding reactions (Table 1, entries 2–3), is apparently the intramolecular C–H insertion to form a β-lactam. The preferential formation of intramolecular products from N,N’-disubstituted diazoacetamides, as compared to diazoacetates has

Gold-catalyzed naphthalene functionalization

• Pedro J. Pérez,
• M. Mar Díaz-Requejo and
• Iván Rivilla

Beilstein J. Org. Chem. 2011, 7, 653–657, doi:10.3762/bjoc.7.77

• bond. In addition, no byproducts derived from carbene coupling were observed. Keywords: carbene insertion; copper catalysts; diazoacetates; gold catalysts; naphthalene functionalization; selective insertion; Introduction At the end of the nineteenth century, Buchner discovered [1] the thermal and

• catalysts, not previously described for the functionalization of such fused arenes. Results and Discussion Reaction of naphthalene and diazoacetates catalyzed by IPrMCl (M = Cu, Au) When dichloroethane solutions of naphthalene were treated with ethyl diazoacetate in the presence of catalytic amounts (5%) of