Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• targeted products were isolated in good yields (Scheme 5). In 2014, Shen and co-workers developed a selective synthesis for methyl 1-benzyl-1H-indole-3-carboxylates and bis(1-benzyl-1H-indol-3-yl)methanones [18] starting from the same kind of substrates used by Gabriele’s group two years before. The first

• -benzyl-1H-indole-3-carboxylates and bis(1-benzyl-1H-indol-3-yl)methanones (bottom). Synthesis of indol-2-acetic esters by Pd(II)-catalyzed carbonylation of 1-(2-aminoaryl)-2-yn-1-ols. Pd(II)-catalyzed carbonylative double cyclization of suitably functionalized 2-alkynylanilines to 3,4-dihydro-1H-furo[3,4

Innovative synthesis of drug-like molecules using tetrazole as core building blocks

• Jingyao Li,
• Ajay L. Chandgude,
• Qiang Zheng and
• Alexander Dömling

Beilstein J. Org. Chem. 2024, 20, 950–958, doi:10.3762/bjoc.20.85

• be a challenging substrate for MCRs and this was also the case for the synthesis of oxo-tetrazoles via a Passerini tetrazole reaction [19]. In a model reaction, we investigated benzyl isocyanide (1 equiv), paraformaldehyde (2 equiv) and trimethylsilyl azide (1 equiv) as easily available substrates

• . Combining water with different co-solvents such as MeOH, DCM, CH3CN and THF provided products generally with low to moderate yields of 29–69% (Table 1, entries 9–14). The low yield of the desired product is either due to the formation of 1-benzyl-1H-tetrazole as side product or low conversion and the oxo

• also well tolerated providing a good yield (62%). The tolerability of different isocyanides, and the possibility to remove the cleavable isocyanides under different reaction conditions (acidic for the tert-octyl and tert-butyl isocyanide, basic for β-cyanoethyl isocyanide, or reductive for the benzyl

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

•  5). A mixture of 2-bromobenzaldehyde (1a, 1 mmol), allylamine hydrochloride (2, 1 mmol), trimethylsilyl azide (3, 1 mmol) and benzyl isocyanide (1 mmol) in MeOH was reacted at 40 °C for 24 h. After evaporating the solvent, 3 mL CH3CN were added to the crude 1,5-DS-1H-T 5a followed by the addition of

• 1 equiv of benzyl bromide and 2 equiv of K2CO3 for the alkylation reaction at 80 °C for 3 h to give N-benzylated compound 7a. Finally, 10 mol % of Pd(OAc)2, 20 mol % of PPh3, 2 equiv of K2CO3 were added to the reaction mixture for the Heck reaction at 105 °C for 3 h under N2 atmosphere to afford

•  5) using seven benzaldehydes 1, two isonitriles 4, and allylamine hydrochloride (2) with trimethylsilyl azide (3) for the Ugi-azide reaction. The N-alkylations were conducted using benzyl bromide and iodomethane, respectively. The final products 8b–j were obtained in 66–74% yields. To evaluate the

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• benzyl alcohol to obtain the unlabelled ester 5 with a quantitative yield over two steps. After having established this method, (5-13C)glutamic acid (3) was converted analogously into (1-13C)-5, unfortunately with a little lower, but still very good yield of 83%. By employing Yamaguchi conditions, the

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• yields (4v–ab, 51–77%). α-Diazo esters with benzyl, cyclobutanemethyl, and adamantyl groups could be transformed smoothly to the products 4v, 4w, and 4x in 64%, 69% and 77% yields, respectively. Gratifyingly, except for acceptor-substituted diazo esters, donor/acceptor-substituted diazo compounds were

• . 1,2-Adducts could be produced fluently with diazo substrates containing alkyl-substituted esters. Benzyl- (6r, 57%), cyclobutanemethyl- (6s, 81%), methoxyethyl- (6t, 66%), and adamantyl- (6u, 82%) substituted diazo esters underwent this photoinitiated radical reaction well. The donor/acceptor

• -substituted diazo compounds with benzyl- and ester groups were also compatible with this MCR system (6v, 78%). Furthermore, the successful transformation of the diazo compounds derived from epiandrosterone (6w, 84%) and testosterone (6x, 56%) highlighted the general utility of this reaction in the

A myo-inositol dehydrogenase involved in aminocyclitol biosynthesis of hygromycin A

• Michael O. Akintubosun and
• Melanie A. Higgins

Beilstein J. Org. Chem. 2024, 20, 589–596, doi:10.3762/bjoc.20.51

• scyllo-inositol but can have reduced activity on ᴅ-chiro-inositol, ᴅ-glucose, ᴅ-xylose and 4-O-benzyl-myo-inositol [12][13][15][16][17]. However, scyllo-inositol dehydrogenases are active on scyllo-inositol and myo-inositol to a lesser extent [16][18]. Altogether, this suggests that Hyg17 can accommodate

Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O–H insertion/base-promoted cyclization involving diazoarylidene succinimides

• Alexander Yanovich,
• Anastasia Vepreva,
• Ksenia Malkova,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 561–569, doi:10.3762/bjoc.20.48

• of compound 4b has been confirmed by single crystal X-ray data. The next step was to investigate the possibility of obtaining six-membered oxygen-containing spiroheterocycles by interaction of DAS 1 with 2-(bromomethyl)benzyl alcohol (15) (Scheme 6). The synthesis was carried out under the conditions

• by the higher reactivity of benzyl bromide and the lower conformational mobility of the side chain with the ortho-phenylene link. As a result, new spirocyclic compounds 5 were obtained in high (5a,b) or moderate (5c) yields. With some other bromo-substituted OH substrates, we obtained O–H insertion

• attack of the oxygen atom of the ester group on the benzyl bromide residue prevails, with the cleavage of the arylidene succinimide fragment involved in further non-selective processes. The causes of the failed cyclizations in the last two cases can be summarized as follows. The intermediates obtained

Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells

• Fumihiro Ishikawa,
• Sho Konno,
• Hideaki Kakeya and
• Genzoh Tanabe

Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39

• Discussion To investigate the influence of the introduction of different alkyl groups at the 2′-OH, we prepared ʟ-Phe-AMS derivatives 4–9. As the compounds 6, 8, and 9 were synthesized previously [20], we designed and synthesized three new ʟ-Phe-AMS derivatives containing methyl (4), benzyl (5), and

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• type addition reactions (Scheme 4A). In 1991, Okada and co-workers reported the addition of alkyl radicals to α,β-unsaturated ketones, by subjecting NHPI esters to visible-light irradiation in the presence of the photocatalyst [Ru(bpy)3]Cl2 and the reductant 1-benzyl-1,4-dihydronicotinamide (BNAH) [37

• the phthalimide moiety (Scheme 7B). Thus, the excited state reductant *IrIII reduces the activated substrate 29 to form the stabilized radical anion 30. Fragmentation into radical 9, followed by radical addition to styrene gives benzyl radical intermediate 26. Turn-over of the catalytic cycle through

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• acenaphthylene 8) or as a result of double protodebromination (giving acenaphthene 5). Overall, the observed process resembles a redox transformation. Benzyl-type anions, which have hydride mobility and are formed in an alkaline environment from 15, may act as a reducing agent here. We tried to stop this

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• of Z-isomers in the photostationary states [42][43]. The introduction of methyl and benzyl substituents in 11a and 18a, respectively, led to a bathochromic shift of the absorption maxima, while introduction of the tert-butyloxycarbonylmethyl substituent in 18c yielded a slight hypsochromic shift due

Optimizations of lipid II synthesis: an essential glycolipid precursor in bacterial cell wall synthesis and a validated antibiotic target

• Milandip Karak,
• Cian R. Cloonan,
• Brad R. Baker,
• Rachel V. K. Cochrane and
• Stephen A. Cochrane

Beilstein J. Org. Chem. 2024, 20, 220–227, doi:10.3762/bjoc.20.22

• using established procedures from the literature, commencing with ᴅ-glucosamine and benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-α-ᴅ-glucopyranoside as the starting materials, respectively [40][41][42][43]. Imidate donors 1a and 1e were obtained exclusively as α-anomers, and 1b and 1g as a 1:1 α:β

• -phosphoryl GlcNAc-MurNAc-pentapeptide 7, based on established protocols with minor adjustments was completed (Scheme 1) [10][11]. After the successful glycosylation reaction, disaccharide 3a, protected with C2-Troc and C6-benzyl groups, was efficiently deprotected under acidic conditions using ZnCl2/Zn

• , followed by in situ re-acetylation of the C2-amino group and C6-alcohol with acetic anhydride, resulting in the formation of disaccharide 4 in a one-pot fashion. The anomeric benzyl protecting group in disaccharide 4 was then removed via a Pd/C-catalyzed hydrogenation reaction, producing a mixture of α/β

Copper-catalyzed multicomponent reaction of β-trifluoromethyl β-diazo esters enabling the synthesis of β-trifluoromethyl N,N-diacyl-β-amino esters

• Youlong Du,
• Haibo Mei,
• Ata Makarem,
• Ramin Javahershenas,
• Vadim A. Soloshonok and
• Jianlin Han

Beilstein J. Org. Chem. 2024, 20, 212–219, doi:10.3762/bjoc.20.21

• side reactions was carried out with benzyl 3-amino-4,4,4-trifluorobutanoate (1a) and benzoic acid (3a) as model substrates. The initial reaction of amine 1a and acid 3a in acetonitrile in the presence of diazotization reagent tert-butyl nitrite with CuI (10 mol %) as catalysts for 2.5 h at room

• system to produce the expected product (4p). In addition, the β-trifluoromethyl β-amino benzyl ester substrates 1 with different ester groups were tried to react with benzoic acid (3a) to further extend the substrate range. To our delight, both the amines with electron-donating groups (4q and 4r) and

Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

• Viktoria A. Ikonnikova,
• Cristina Cheibas,
• Oscar Gayraud,
• Alexandra E. Bosnidou,
• Nicolas Casaretto,
• Gilles Frison and
• Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

• one-pot transformation from readily available benzyl(prenyl)malonate substrates. After the photooxygenation of the prenyl moiety, the resulting hydroperoxide was directly engaged in a Hock cleavage by adding a Lewis acid. The presence of an aromatic nucleophile in the reaction mixture and that of a

• benzyl moiety on the substrate resulted in tandem Friedel–Crafts reactions to form the 1-aryltetraline products. These compounds share a close analogy to the cyclolignan natural products. Experimental observations and a DFT study support the involvement of an aldehyde intermediate during the Friedel

• substrates to be submitted to the one-pot tandem transformation (Scheme 5). With only a few exceptions, the presence of ortho (R1), meta (R2), or para (R3) substituents on the benzyl moiety generally allowed the intramolecular Friedel–Crafts reaction, after the first intermolecular one in the presence of

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

• Changdong Shao,
• Chen Ma,
• Li Li,
• Jingyi Liu,
• Yanan Shen,
• Chen Chen,
• Qionglin Yang,
• Tianyi Xu,
• Zhengsong Hu,
• Yuhe Kan and
• Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

• . The scope of the bromination reaction was further extended with various alkyl bromides. As shown in Scheme 3, a series of activated alkyl bromides containing ester, difluoromethylene, benzyl motifs (2b–f), and unactivated alkyl bromides (2g–i) were evaluated in this reaction. Activated alkyl bromides

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

• Pavel S. Silaichev,
• Tetyana V. Beryozkina,
• Vsevolod V. Melekhin,
• Valeriy O. Filimonov,
• Andrey N. Maslivets,
• Vladimir G. Ilkin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

• -triazole-4-carbimidamides with alkyl, allyl, propargyl, benzyl, cycloalkyl, and indolyl substituents at the N1 position . Keywords: Cornforth rearrangement; cycloaddition reactions; 3,3-diaminoacrylonitriles; heterocyclic azides; 1,2,3-triazole; Introduction Heteroaryl amidines are widely used in the

• previously unknown 5-amino-1-substituted 1,2,3-triazole-N-heteroaryl-4-carboximidamides 3 bearing alkyl, allyl, propargyl, benzyl, cycloalkyl, and various heteroaryl substituents at the N1 postion of the carbimidamide group. Herein, we disclose our results on the cycloaddition reaction of 3,3

• -(benzylamino)acrylonitrile (1a) to 6-azidopyrimidine-2,4-dione 2a (Table 1). To our surprise we obtained (Z)-5-amino-1-benzyl-N'-(1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-yl)-1H-1,2,3-triazole-4-carboximidamide (3a) in 93% yield as the major product with 5-amino-1-benzyl-1H-1,2,3-triazole-4

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• ) depending on the nature of their aliphatic or aromatic substituents, and that the use of the stronger base KN(SiMe3)2 (pKa = 26) was not always mandatory [25][69][70]. Grubbs, Bertrand et al. also noticed that treating 1-benzyl-3-methyl-4-phenyl-1H-1,2,3-triazolium iodide with KOt-Bu did not afford the

Construction of diazepine-containing spiroindolines via annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates

• Xing Liu,
• Wenjing Shi,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1923–1932, doi:10.3762/bjoc.19.143

• evaporation at reduced pressure, the residue was subjected to column chromatography with ethyl acetate, dichloromethane and petroleum ether 1:3:7 (v/v/v) to give pure product for analysis. 1'-Benzoyl-1-benzyl-5-methyl-2-oxo-3'-phenyl-1',4'-dihydrospiro[indoline-3,5'-[1,2]diazepine]-6'-carbonitrile (3a

• rotatory evaporation at reduced pressure, the residue was subjected to column chromatography with ethyl acetate, dichloromethane and petroleum ether 1:3:7 (v/v/v) to give pure product for analysis. Methyl 1'-benzoyl-1-benzyl-5-chloro-2-oxo-3'-phenyl-1',4'-dihydrospiro[indoline-3,5'-[1,2]diazepine]-6

• at reduced pressure, the residue was subjected to column chromatography with ethyl acetate, dichloromethane, and petroleum ether 1:3.7 (v/v/v) to give pure product for analysis. 1-Benzyl-2-oxo-3'-(p-tolyl)-1'-tosyl-1',4'-dihydrospiro[indoline-3,5'-[1,2]diazepine]-6'-carbonitrile (7a): white solid, 64

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• dimers reduce halides that have reduction potentials less cathodic than ca. −2 V vs ferrocenium/ferrocene, especially under UV photoexcitation (using a 365 nm LED). In the case of benzyl halides, the products are bibenzyl derivatives, whereas aryl halides are reduced to the corresponding arenes. The

• . −2 V vs FeCp2+/0, yet the dimers are reasonably stable to air due to the kinetic barriers associated with the coupling of electron-transfer and bond-cleavage reactions [26]. Here we demonstrate that (N-DMBI)2 and (Cyc-DMBI)2 (Figure 1c) can be used to accomplish dehalogenation of benzyl, alkyl, and

• aryl halides (RX) and discuss the scope and possible mechanism of these reactions. Results and Discussion Reaction of (Y-DMBI)2 with benzyl bromide We began our investigations of dehalogenation reactions using benzyl bromide (BnBr, 1a), which has a reduction peak potential (Epc) of −1.6 V vs FeCp2+/0

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• , such as alkyl halides. In this study, the thermal reaction of the La@C2v-C82 anion with benzyl bromide derivatives 1 at 110 °C afforded single-bonded adducts 2–5 with high regioselectivity. The products were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

• reaction is believed to occur via electron transfer, followed by the radical coupling of La@C2v-C82 and benzyl radicals, rather than by bimolecular nucleophilic substitution reaction of La@C2v-C82 anion with 1. Keywords: electron transfer; metallofullerene; radical; reduction; Introduction Fullerenes

• more localized on the inside of the cluster for [Sc3N@Ih-C80]2−. A previous study reported that thermal treatment of La@C2v-C82 in the presence of 3-triphenylmethyl-5-oxazolidinone in toluene afforded four different benzylated La@C2v-C82 isomers [19]. Benzyl radicals may have been generated due to the

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• yields of the desired products 3. On the other hand, when R2 was aryl or benzyl the yields of 3 over two steps were very good, in the range of 75–92% (Table 1). The R1 substituent influenced the yield of 3 to a lower extent, but with an unfavorable effect of sterically bulkier substituents. Any α

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• radical and I· played a pivotal as an intermediate step in the production of alkyl iodides B. Compound B could undergo a further elimination reaction to yield various olefins 11. Regarding benzyl substrates, the radical I· demonstrated its efficacy as a reagent for hydrogen atom transfer (HAT

• ), specifically by extracting a hydrogen atom from the α-position of benzyl radicals A. The process described above led to the formation of the corresponding olefins 11, eliminating the need for a carbon–iodine bond formation step. Alkylation Diaziridines are highly versatile building blocks in synthesis, with

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• complex obtainable via a straightforward synthesis, with improved solubility, concerning our previous Co(II) complexes [21]. Thus, the new Co(II) complex bears two 1-benzyl-4-(quinolin-2-yl)-1H-1,2,3-triazole (BzQuTr) units, that were obtained through a copper-catalyzed alkyne–azide cycloaddition (CuAAC

• maintaining high selectivity for carbon products. Results and Discussion Synthesis and characterization of the new Co(II)-based catalyst The novel cobalt(II) complex 1 was synthesized in dry methanol (MeOH) by mixing in a 2:1 ratio, the chelating diimine ligand, 1-benzyl-4-(quinolin-2-yl)-1H-1,2,3-triazole

A series of perylene diimide cathode interlayer materials for green solvent processing in conventional organic photovoltaics

• Kathryn M. Wolfe,
• Shahidul Alam,
• Eva German,
• Fahad N. Alduayji,
• Maryam Alqurashi,
• Frédéric Laquai and
• Gregory C. Welch

Beilstein J. Org. Chem. 2023, 19, 1620–1629, doi:10.3762/bjoc.19.119

• new cathode interlayer (CIL) materials based on bay N-annulated perylene diimides. Starting from the previously reported N-annulated perylene diimide (PDIN-H), the N-position was functionalized with a benzyl and pentafluorobenzyl group to make PDIN-B and PDIN-FB, respectively. Similarly, starting from

• the previously reported cyanated N-annulated perylene diimide (CN-PDIN-H), the N-position was functionalized with a benzyl and pentafluorobenzyl group to make CN-PDIN-B and CN-PDIN-FB, respectively. The materials exhibit solubility in the green solvent, ethyl acetate, and thus were processed into thin

• the previously reported N-annulated PDI (PDIN-H) and nitrile functionalized N-annulated PDI (CN-PDIN-H) compounds (Figure 1c) as the scaffolds for modification [18]. The PDIN-H scaffold was modified by N-functionalization with a benzyl (PDIN-B) or pentafluorobenzyl group (PDIN-FB). Similarly, the CN

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• and benzyl azides was examined. An array of para- and meta-substituted aryl azides was amenable to the optimized conditions. The presence of electron-withdrawing groups worked well affording the products with m-cyano (4a), 3,5-dimethoxy (4b), m-fluoro (4c), and p-chloro (4d) substitution in 39–58

• reaction faster than electron-donating groups. Similar trends were observed for benzyl azides; however, this substituent was much less reactive compared to its aryl counterparts. It required a higher temperature of 110 °C and a longer duration of the reaction (72 h). The product with an electron

• Equiv of CuSO4 was used as an additive. bModified reaction conditions for benzyl azides: 1 (1 equiv), 2 (1.5 equiv) 0.4 equiv of LiHMDS (1 M in THF), morpholine (0.34–0.4 M), 110 °C, 72 h. Time course profile monitored by 19F NMR spectroscopy. NOESY of 4e confirming the regiochemistry of the product