Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• of the Co–H to the alkene but of a step-wise radical addition. A similar procedure was reported by Herzon [85]. His study focused on the use of two reductants, triethylsilane and 1,4-dihydrobenzene (DHB) (Scheme 24). He showed that in the presence of DHB, the intermediate radical could be trapped by

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

• after appropriate modification led to the alkynyl aldehyde cyclization precursor 154. The ring closure was performed under catalytic reductive conditions in the presence of Ni(cod)2 and ligand 155 as the catalytic system, and triethylsilane as a reductant. The expected cycloadduct was obtained as a

First series of N-alkylamino peptoid homooligomers: solution phase synthesis and conformational investigation

• Maxime Pypec,
• Laurent Jouffret,
• Claude Taillefumier and
• Olivier Roy

Beilstein J. Org. Chem. 2022, 18, 845–854, doi:10.3762/bjoc.18.85

• ]. In this seminal publication, hydrazones were utilized as submonomers in the displacement step of resin-bound bromoacetylated peptoids and cleavage from the resin with TFA containing 5% of triethylsilane resulted in a concomitant reduction of the imine functions in N-alkylamino groups. In this work

New synthesis of a late-stage tetracyclic key intermediate of lumateperone

• Mátyás Milen,
• Bálint Nyulasi,
• Tamás Nagy,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2022, 18, 653–659, doi:10.3762/bjoc.18.66

• with triethylsilane in TFA to cis-racemate 15. The key step of the syntheses is the resolution of this intermediate with (R)-mandelic acid. The enantiomerically pure (R)-mandelate salt 16 thus obtained was reacted with ethyl chloroformate to give 17. It was then transformed to tetracyclic derivative 8

Novel library synthesis of 3,4-disubstituted pyridin-2(1H)-ones via cleavage of pyridine-2-oxy-7-azabenzotriazole ethers under ionic hydrogenation conditions at room temperature

• Romain Pierre,
• Anne Brethon,
• Sylvain A. Jacques,
• Aurélie Blond,
• Sandrine Chambon,
• Sandrine Talano,
• Catherine Raffin,
• Branislav Musicki,
• Claire Bouix-Peter,
• Loic Tomas,
• Gilles Ouvry,
• Rémy Morgentin,
• Laurent F. Hennequin and
• Craig S. Harris

Beilstein J. Org. Chem. 2021, 17, 156–165, doi:10.3762/bjoc.17.16

• a trifluoroacetamide impurity, presumably forming by reaction with the cyclohexylamine moiety. In the absence of triethylsilane (TES), only deprotection of the Boc group was observed when using TFA (Table 3, entry 8) and when the reaction was carried out in mixture of TFA/H2O (4:1) over 4 days, only

• hydrogenation [15], through addition of the hydride from triethylsilane to afford 1 after in situ hydrolysis of the triethylsilyloxy bond. HOAt alone does not degrade under these conditions and intermediate 21 has been identified and characterized from the reaction medium although we did not identify 2

Deoxyfluorination of acyl fluorides to trifluoromethyl compounds by FLUOLEAD^®/Olah’s reagent under solvent-free conditions

• Yumeng Liang,
• Akihito Taya,
• Zhengyu Zhao,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2020, 16, 3052–3058, doi:10.3762/bjoc.16.254

• they only provided two examples. In 2018, Schoenebeck and co-workers reported the decarbonylative trifluoromethylation of acyl fluorides by trifluoromethyl triethylsilane (Et3SiCF3) under Pd catalysis at high temperature (Scheme 1b) [26], although the reaction was categorized as trifluoromethylation

Synthesis of monophosphorylated lipid A precursors using 2-naphthylmethyl ether as a protecting group

• Jundi Xue,
• Ziyi Han,
• Gen Li,
• Khalisha A. Emmanuel,
• Cynthia L. McManus,
• Qiang Sui,
• Dongmian Ge,
• Qi Gao and
• Li Cai

Beilstein J. Org. Chem. 2020, 16, 1955–1962, doi:10.3762/bjoc.16.162

• -naphthaldehyde, trimethylsilyl trifluoromethanesulfonate (TMSOTf), and triethylsilane (Et3SiH) [17][19]. On a 10 g scale, the protected methyl ester 6 could be purified by recrystallization followed by filtration to remove the major byproduct 2-methylnaphthalene. Subsequent saponification of the methyl ester 6

Synthesis of the tetrasaccharide repeating unit of the O-specific polysaccharide of Azospirillum doebereinerae type strain GSF71^T using linear and one-pot iterative glycosylations

• Arin Gucchait,
• Pradip Shit and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2020, 16, 1700–1705, doi:10.3762/bjoc.16.141

• treatment with HClO4-SiO2 [34]; (c) selective acetylation of the primary hydroxy group, and (d) removal of the benzyl groups by catalytic transfer hydrogenation [35] using triethylsilane in the presence of Pearlman’s catalyst [36] to furnish the desired tetrasaccharide 1 in 50% overall yield with the two O

Synthesis of 3-substituted isoxazolidin-4-ols using hydroboration–oxidation reactions of 4,5-unsubstituted 2,3-dihydroisoxazoles

• Lívia Dikošová,
• Júlia Laceková,
• Ondrej Záborský and
• Róbert Fischer

Beilstein J. Org. Chem. 2020, 16, 1313–1319, doi:10.3762/bjoc.16.112

• readily obtained through the reductive cleavage of benzoylated isoxazolidines, employing the Lewis acid-catalyzed SN reaction with triethylsilane as the hydride source (Scheme 1). For this reason, the benzoates 6a and 6b were readily prepared from the corresponding 2,3-dihydroisoxazoles 5a and 5b

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

Design and synthesis of multivalent α-1,2-trimannose-linked bioerodible microparticles for applications in immune response studies of Leishmania major infection

• Chelsea L. Rintelmann,
• Tara Grinnage-Pulley,
• Kathleen Ross,
• Daniel E. K. Kabotso,
• Angela Toepp,
• Anne Cowell,
• Christine Petersen,
• Balaji Narasimhan and
• Nicola Pohl

Beilstein J. Org. Chem. 2019, 15, 623–632, doi:10.3762/bjoc.15.58

• was selectively hydrolyzed with CH2Cl2/TFE/AcOH 3:1:1 and trapped by triethylsilane, providing free amine 23 [54]. At this point, the epsilon amine 23 was coupled with TAMRA-NHS, followed by acidic deprotection of the tert-butyl esters to afford the triacid 25. Then, the successful coupling of the

Synthesis and SAR of the antistaphylococcal natural product nematophin from Xenorhabdus nematophila

• Frank Wesche,
• Hélène Adihou,
• Thomas A. Wichelhaus and
• Helge B. Bode

Beilstein J. Org. Chem. 2019, 15, 535–541, doi:10.3762/bjoc.15.47

• aluminium chloride (AlCl3) in DCM to give compounds 14 and 21. Subsequent reduction was achieved with triethylsilane (Et3SiH) in TFA to give 15 and 22. For the synthesis of the primary amine, halides 15 and 22 were converted in a Gabriel synthesis with potassium phthalimide in DMF to the appropriate

Silanediol versus chlorosilanol: hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes

• Falco Fox,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2019, 15, 167–186, doi:10.3762/bjoc.15.17

• additional substituents (TS = transition structure) [62][63][64][65][66][67][68]. Hydrogen-bond-catalyzed N-acyl Mannich reaction of in situ-generated 10 with different silyl ketene acetals 11 a–d and BIFOXSi(OH)2 (9) yielding C–C coupling product 12 (Tables 6–8); (TMS: trimethylsilane. TES: triethylsilane

Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate

• Eloi P. Coutant,
• Vincent Hervin,
• Glwadys Gagnot,
• Candice Ford,
• Racha Baatallah and
• Yves L. Janin

Beilstein J. Org. Chem. 2018, 14, 2853–2860, doi:10.3762/bjoc.14.264

• boron-based complexes. In an attempt to improve this, we applied the reported use of triethylsilane for reducing oximes into N-hydroxylamines [17] to the case of the α-hydroxyimino ester 2a. However, bringing the reduction of 2a into the N-hydroxylamino derivative 42 to completion with this reagent

• still required a repeated addition of triethylsilane over a week and led to a 69% isolated yield. Interestingly, further literature search pointed out a very different synthetic access to such N-hydroxylamine derivative (via nitrones) which appears to be far more efficient [18][19][20][21][22]. The

Synthesis of α-D-GalpN₃-(1-3)-D-GalpN₃: α- and 3-O-selectivity using 3,4-diol acceptors

• Emil Glibstrup and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2018, 14, 2805–2811, doi:10.3762/bjoc.14.258

• from the common 2-azidoglucose precursor 7, the 4,6-O-benzylidene group was removed with TsOH to give the 4,6-diol in 95% yield, followed by selective 6-O-protection using TBDPS-Cl and imidazole (IM) in 90% yield. The 4,6-O-benzylidene motif could also be regioselectively opened using triethylsilane

Cobalt bis(acetylacetonate)–tert-butyl hydroperoxide–triethylsilane: a general reagent combination for the Markovnikov-selective hydrofunctionalization of alkenes by hydrogen atom transfer

• Xiaoshen Ma and
• Seth B. Herzon

Beilstein J. Org. Chem. 2018, 14, 2259–2265, doi:10.3762/bjoc.14.201

• -butyl hydroperoxide (TBHP), and triethylsilane (Et3SiH) constitute an inexpensive, general, and practical reagent combination to initiate a broad range of Markovnikov-selective alkene hydrofunctionalization reactions. These transformations are believed to proceed by cobalt-mediated hydrogen atom

• triethylsilane (Et3SiH). The practicality and generality of this system should motivate its application in synthesis. Results and Discussion In 2014, we reported the reduction of alkenyl halides (e.g., 1, Scheme 2) utilizing Co(acac)2, TBHP, and two reductants, triethylsilane and 1,4-dihydrobenzene (DHB) [2

Recent advances in synthetic approaches for medicinal chemistry of C-nucleosides

• Kartik Temburnikar and
• Katherine L. Seley-Radtke

Beilstein J. Org. Chem. 2018, 14, 772–785, doi:10.3762/bjoc.14.65

• -dideazaadenine to obtain the lactol intermediate (Figure 7A) [63][65][69][70]. Deoxygenation of the lactol intermediate by BF3·OEt2 resulted in the oxocarbenium ion, which was then reduced using triethylsilane to obtain 2. Replacing triethylsilane with allyl trimethylsilane and trimethylsilyl cyanide gave C1

Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2017, 13, 960–987, doi:10.3762/bjoc.13.97

• remove the Pd catalyst. The nitroaromatic derivative is mixed with triethylsilane and the mixture is passed through a fixed bed reactor with Pd/C catalyst at 40 °C to reduce the nitro group to an amino group. The yield is reported to be quantitative, and the catalyst activity is reported to be lasted for

• can be quenched by distilled water and extracted in a column, where again the distilled water flow rate can be controlled using a ratio controller. Filtration can remove the Pd catalyst in a continuous manner. This process stream can be further mixed with preheated triethylsilane at appropriate molar

Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• subsequently converted to the fucosyl trichloroacetimidate building block 8 (Scheme 5). Galactosyl thioglycoside 9 was prepared from D-galactose following published procedures [32]. Reductive opening of the benzylidene acetal of known galactosyl thioglycoside 29 [33] with triethylsilane [34] in TFA/CH2Cl2

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• filtration through a silica packed cartridge, the resulting reaction stream was mixed with triethylsilane (124) and telescoped into a Pd-doped fixed bed reactor in order to affect smooth reduction of the nitro group. The output stream was then collected, and reintroduced to a flow reactor to be combined with

Efficient carbon-Ferrier rearrangement on glycals mediated by ceric ammonium nitrate: Application to the synthesis of 2-deoxy-2-amino-C-glycoside

• Alafia A. Ansari,
• Y. Suman Reddy and
• Yashwant D. Vankar

Beilstein J. Org. Chem. 2014, 10, 300–306, doi:10.3762/bjoc.10.27

• Hayashi and co-workers [47], which described the obtainment of Ferrier products along with C-3 substituted products. On the other hand, glucal 1a on reaction with triethylsilane afforded the product 7 in 43% yield, while galactal 1b gave a complex mixture of products, which could not be analyzed. Proposed

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• the Co(II)/Et3SiH/O2 system (Isayama–Mukaiyama reaction) Peroxysilylation of alkenes with molecular oxygen in the presence of triethylsilane catalyzed by cobalt(II) diketonates was described for the first time by S. Isayama and T. Mukaiyama in 1989 [246][247]. Currently, this approach is one of the

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• Pd-catalyzed aromatic trifluoromethylation of aryl chlorides with a nucleophilic source of CF3 has been reported in 2010 by S. L. Buchwald et al. (Table 2) [38]. An excess of expensive (trifluoromethyl)triethylsilane (TESCF3) in combination with potassium fluoride was used to provide the expected

A practical synthesis of long-chain iso-fatty acids (iso-C₁₂–C₁₉) and related natural products

• Mark B. Richardson and
• Spencer J. Williams

Beilstein J. Org. Chem. 2013, 9, 1807–1812, doi:10.3762/bjoc.9.210

• triethylsilane and BF3·Et2O [53], affording 11. Oxidative cleavage of 11 with KMnO4/Bu4NBr [54] afforded iso-C12 acid 1. Alternatively, anti-Markovnikov hydration of 11, using I2/NaBH4 then hydrogen peroxide [55], afforded the alcohol 12, and oxidation of 12 with KMnO4/Bu4NBr afforded iso-C13 acid 2

• using triethylsilane/BF3·Et2O [53], yielding 17. Finally, oxidation of 17 with KMnO4/Bu4NBr [54] afforded the iso-C17 acid 6. The iso-C15 acid 4 and iso-C16 acid 5 were prepared by recursive dehomologation through intercepting the alcohol 17. Preparation of the xanthate ester 18 (NaH, CS2, then MeI) [58

• ; triethylsilane/BF3·Et2O [53] reduction gave 25; and KMnO4/Bu4NBr oxidation afforded iso-C18 acid 7 (Scheme 3). The iso-C19 acid 8 was readily prepared by a three-step homologation through intercepting the alcohol 25. Thus, mesylation of 25 (MsCl/Et3N [56]) afforded 26; substitution (KCN/DMSO) afforded the

Straightforward synthesis of a tetrasaccharide repeating unit corresponding to the O-antigen of Escherichia coli O16

• Manas Jana and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2013, 9, 1757–1762, doi:10.3762/bjoc.9.203

• transfer hydrogenation with triethylsilane and 10% Pd/C [20]; (b) an acetylation using acetic anhydride and pyridine, and (c) a saponification reaction with sodium methoxide to furnish compound 1, which was purified over a Sephadex® LH-20 gel to give the pure compound 1 in 64% overall yield. The structure