The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• levulinoyl protecting group, the 4,4-(ethylenedithio)pentanoyl group 28 [99]. Wong and co-workers illustrated the selective activation (Scheme 5) of C-2 levulinoyl-protected thiotolyl glycopyranosyl donor 29 for the synthesis of the disaccharide fragment 31 of fucosyl ganglioside GM1 [100]. Pivalate

Streamlined modular synthesis of saframycin substructure via copper-catalyzed three-component assembly and gold-promoted 6-endo cyclization

• Asahi Kanno,
• Ryo Tanifuji,
• Satoshi Yoshida,
• Sota Sato,
• Saori Maki-Yonekura,
• Kiyofumi Takaba,
• Jungmin Kang,
• Kensuke Tono,
• Koji Yonekura and
• Hiroki Oguri

Beilstein J. Org. Chem. 2025, 21, 226–233, doi:10.3762/bjoc.21.14

• measurements (Figures S20 to S25, Supporting Information File 1). A notable feature of this cascade process is the temporary protection of the C≡N triple bond, nitrile in the key intermediate 11, by the 2,3-diaminobenzofuran group. This facilitates the site-selective activation of the alkyne triple bond by the

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• , along with electrostatic and hydrogen-bonding interactions. This behavior not only allowed for the selective activation and deactivation of organocatalytic activity but also facilitated efficient catalyst recovery at the end of the catalytic reaction. Notably, control experiments supported the

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

• dihydrofurans [102]. In 2019, the Li group studied the selective activation of the α-C(sp3)–H of ketones and esters 103 for the tandem addition/cyclization of o-vinylanilides 102 (Scheme 20) [103]. Through a series of mechanistic experiments, it was noted the cleavage of the C(sp3)–H bond may be involved in the

Photocontrolled DNA minor groove interactions of imidazole/pyrrole polyamides

• Sabrina Müller,
• Jannik Paulus,
• Jochen Mattay,
• Heiko Ihmels,
• Veronica I. Dodero and
• Norbert Sewald

Beilstein J. Org. Chem. 2020, 16, 60–70, doi:10.3762/bjoc.16.8

• (Py/Im) and TA (Hp/Py). However, N-methylhydroxypyrrole (Hp) is neither easy to synthesize nor sufficiently stable. In practice, therefore, Py/Py is used to address both AT and TA. Along this line, it is attractive to incorporate a molecular switch for the selective activation of an initially inactive

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

Selective carboxylation of reactive benzylic C–H bonds by a hypervalent iodine(III)/inorganic bromide oxidation system

• Toshifumi Dohi,
• Shohei Ueda,
• Kosuke Iwasaki,
• Yusuke Tsunoda,
• Koji Morimoto and
• Yasuyuki Kita

Beilstein J. Org. Chem. 2018, 14, 1087–1094, doi:10.3762/bjoc.14.94

• single-electron-transfer (SET) reactivities [33][34][35][36][37] allow selective activation of the benzylic C(sp3)–H bond for oxidative functionalization and coupling reactions. Initially, the SET oxidation ability of pentavalent iodine reagents, especially o-iodoxybenzoic acid (IBX), in benzylic

Cross-coupling of dissimilar ketone enolates via enolonium species to afford non-symmetrical 1,4-diketones

• Keshaba N. Parida,
• Gulab K. Pathe,
• Shimon Maksymenko and
• Alex M. Szpilman

Beilstein J. Org. Chem. 2018, 14, 992–997, doi:10.3762/bjoc.14.84

• of ketone enolates to give 1,4-dicarbonyl compounds [26]. However, the radical-based method of Baran and the umpolung method of Maulide both take advantage of the selective activation of an amide and are therefore not amenable to ketone enolates. MacMillan reported the organocatalytic oxidative

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• phthaloyl linkers in terms of stereoselectivity and yields. Thus, a tethered donor-central unit conjugate 53 was coupled with the BPA-conjugated glycosyl acceptor 54 using DCC/DMAP-mediated coupling reaction to obtain the templated conjugate of three monosaccharide units 55 in 82% yield. The selective

• activation of the S-ethyl leaving group in compound 55 was achieved with MeOTf and the glycosylation of the central building block took place with concomitant removal of the p-methoxybenzyl (PMB) group. The o-allylphenyl leaving group was activated with NIS/TfOH, and again the PMB group of the acceptor was

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

• moieties. Nonetheless, by taking advantage of the differential reactivity of the anomeric center, a selective activation at this position is possible. As a result, protecting group-free strategies to effect glycosylations are available thanks to the tremendous efforts of many research groups. In this

• review, we showcase the methods available for the selective activation of the anomeric center on the glycosyl donor and the mechanisms by which the glycosylation reactions take place to illustrate the power these techniques. Keywords: glycosides; glycosylation; oligosaccharides; protecting groups

• , and co-workers [11]. While their review is a comprehensive overview of many diverse glycosylation strategies, we offer a more detailed account of the methods developed in the last two decades with the main focus on the processes developed for the selective activation of the anomeric center, hence

A concise enantioselective synthesis of the guaiane sesquiterpene (−)-oxyphyllol

• Martin Zahel and
• Peter Metz

Beilstein J. Org. Chem. 2013, 9, 2028–2032, doi:10.3762/bjoc.9.239

• this end, we tried to prepare the thionocarbonate 8 from 7 with phenyl chlorothionoformate [9][10]. However, all attempts at selective activation of the secondary hydroxy group led to the cyclic product 9 instead. A similar problem was already encountered earlier [11]. Scheme 3 depicts the efficacious

Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

• Maurizio Fagnoni,
• Stefano Protti,
• Davide Ravelli and
• Angelo Albini

Beilstein J. Org. Chem. 2013, 9, 800–808, doi:10.3762/bjoc.9.91

• processes have found some application in synthesis for the mild and selective activation of aliphatic derivatives, in particular of a C–H bond [32]. The role of the acceptor radical anion in the above processes is thus decisive, and we report below a steady-state investigation of such species arising from

Asymmetric synthesis of a highly functionalized bicyclo[3.2.2]nonene derivative

• Toshiki Tabuchi,
• Daisuke Urabe and
• Masayuki Inoue

Beilstein J. Org. Chem. 2013, 9, 655–663, doi:10.3762/bjoc.9.74

• selective activation of acrolein in the presence of the Lewis-basic allylic oxygen was a prerequisite to the successful formation of 8. We anticipated that bulky trialkylsilyl triflates would function as such chemoselective Lewis acids, because the activation of the TBS-connected oxygen of 7 by the silyl

Organocatalytic C–H activation reactions

• Subhas Chandra Pan

Beilstein J. Org. Chem. 2012, 8, 1374–1384, doi:10.3762/bjoc.8.159

• chirality in cationic intermediate C (Scheme 13). Nucleophilic attack then occurred from the same side of the transferred hydrogen to provide (S)-19. The authors concluded that selective activation of one of the enantiotopic hydrogen atoms by chiral phosphoric acid is the main reason for obtaining

2-Allylphenyl glycosides as complementary building blocks for oligosaccharide and glycoconjugate synthesis

• Hemali D. Premathilake and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2012, 8, 597–605, doi:10.3762/bjoc.8.66

• efficient oligosaccharide assembly. Keywords: carbohydrates; glycosylation; leaving group; oligosaccharides; orthogonal strategy; selective activation; Introduction Current knowledge about the key roles of carbohydrates is still limited. However, thanks to the explosive growth of the field of glycobiology

• oligosaccharide assembly by minimizing or even eliminating additional manipulations between coupling steps, are based either on chemoselective or on selective activation of leaving groups [6]. The use of selective activation [7] offers more flexibility than that of the chemoselective activation which relies on

• the nature of the protecting groups [8], and Ogawa’s orthogonal strategy is conceptually the most attractive approach that has been developed to date [9][10][11][12]. This technique implies the use of two orthogonal leaving groups, LGa and LGb, the selective activation of which can be reiterated to

Triazole–Au(I) complex as chemoselective catalyst in promoting propargyl ester rearrangements

• Dawei Wang,
• Yanwei Zhang,
• Rong Cai and
• Xiaodong Shi

Beilstein J. Org. Chem. 2011, 7, 1014–1020, doi:10.3762/bjoc.7.115

• process [35]. As shown in Scheme 2b, with the [IPr–Au]+ catalyst, only trace amount of the allene 2a was obtained. The major product derived from the Friedel–Crafts addition of the aromatic ring to the gold activated allene. Therefore, selective activation of the alkyne over the allene was considered as a

Gold-catalyzed heterocyclizations in alkynyl- and allenyl-β-lactams

• Benito Alcaide and
• Pedro Almendros

Beilstein J. Org. Chem. 2011, 7, 622–630, doi:10.3762/bjoc.7.73

• (DFT) calculations were performed to obtain insight on various aspects of this reactivity and indicated the selective activation of the allene and alkyne component. Free energy profile [kcal mol–1] for the transformation of γ-allenol I into the tetrahydrofuran type 9. Gold-catalyzed cyclization of 4

Diels- Alder reactions using 4,7-dioxygenated indanones as dienophiles for regioselective construction of oxygenated 2,3-dihydrobenz[f]indenone skeleton

• Natsuno Etomi,
• Takuya Kumamoto,
• Waka Nakanishi and
• Tsutomu Ishikawa

Beilstein J. Org. Chem. 2008, 4, No. 15, doi:10.3762/bjoc.4.15

• -Trioxygenated 2,3-dihydrobenz[f]indenone derivative 21 was exclusively formed on DAR of indanetrione 8 and diene 7 because of selective activation of the C6 carbon due to the presence of additional cross conjugation between the C1 and the C4 carbonyl groups (TS-A, Figure 4). Semiempirical calculation [44] of

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

• hydroxyl groups. Selective activation of the allylic alcohol in 2 as a leaving group followed by nucleophilic attack by the homoallylic alcohol will lead to dihydropyran 3. However, activation of the homoallylic alcohol followed by nucleophilic attack by the allylic alcohol will provide the enantiomeric