The Ugi4CR as effective tool to access promising anticancer isatin-based α-acetamide carboxamide oxindole hybrids

• Carolina S. Marques,
• Aday González-Bakker and
• José M. Padrón

Beilstein J. Org. Chem. 2024, 20, 1213–1220, doi:10.3762/bjoc.20.104

• -acetamide carboxamide isatin hybrids 8 easy accessed via deprotection reaction on the Ugi-adducts 5 and 7. TFA: trifluoroacetic acid. Supporting Information Supporting Information File 56: Experimental procedures, analytical data, NMR spectra and biological assays. Funding C. S. M. thanks the Norma

Introduction of peripheral nitrogen atoms to cyclo-meta-phenylenes

• Koki Ikemoto and
• Hiroyuki Isobe

Beilstein J. Org. Chem. 2024, 20, 1207–1212, doi:10.3762/bjoc.20.103

• total, 3a was obtained in 7% yield (325 mg, 0.707 mmol). N3-[6]CMP (3a): 1H NMR (CDCl3, 600 MHz) δ 9.05 (d, J = 2.1 Hz, 6H), 8.58 (t, J = 2.1 Hz, 3H), 8.23 (t, J = 2.1 Hz, 3H), 7.89 (dd, J = 7.6, 2.1 Hz, 6H), 7.69 (t, J = 7.6 Hz, 3H); 13C NMR (CDCl3, 150 MHz) δ 146.6 (CH), 138.3, 135.7, 133.9 (CH

• ), 130.2 (CH), 127.5 (CH), 125.9 (CH); HRMS (APCI) (m/z): [M + H]+ calcd. for C33H22N3, 460.1808; found, 460.1808. N4-[8]CMP (3b): 1H NMR (CDCl3, 600 MHz) δ 8.81 (d, J = 1.4 Hz, 8H), 8.13 (t, J = 1.4 Hz, 4H), 7.76 (s, 4H), 7.66–7.73 (m, 12H); 13C NMR (CDCl3, 150 MHz) δ 147.9 (CH), 139.2, 137.0, 133.5 (CH

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• ] [5]. In the case of 3, the e′ and e′′ isomers are identical products, and 3 is denoted as the e isomer hereinafter. The 1H NMR spectrum of 3 showed signals of eight doublets and three septets, which were assigned respectively to the methyl and methine groups, along with the aromatic protons (Figure 3

• ). In the 13C NMR spectrum, a total of 43 signals were observed in the low-field region (approximately 160–120 ppm), of which 29 signals are attributed to the C60 carbon cage and 14 signals are attributed to the aromatic ring carbon nuclei of the Dip groups (Figure 4). In addition, three sp3 carbon

• . Reagents were used as purchased unless otherwise specified. The 1H and 13C NMR measurements were conducted on a JEOL ECA-500 spectrometer (JEOL Ltd.). Absorption spectra were measured using a UV-3150 spectrophotometer (Shimadzu Corp.). Cyclic voltammograms and differential pulse voltammograms were recorded

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• reactivity of 9dc,dl. Supporting Information Supporting Information File 26: Experimental section and copies of 1H and 13C NMR spectra of all new compounds. Funding The authors thank the São Paulo Foundation Science (FAPESP, #2018/02611-0, #2013/07600-3 and #2023/18007-3, to FC) for financial support. F. C

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• then undergo condensation with formaldehyde providing an N-phenylmethanimine intermediate which was confirmed by 1H NMR spectroscopy. In the final step, the imine undergoes hydrogenation with Mn3-b to yield the N-methylated product (Scheme 16). In 2020, Maji et al. synthesized manganese(I) complexes

• . Furthermore, β-alkylation of 1-phenyl-1-ethanol with benzylic alcohols was also studied with 2 mol % of the Mn4 pre-catalyst, 5 mol % of Cs2CO3 in t-AmOH at 135 °C for 20 h (Scheme 32). NMR studies endorsed the formation of intermediates such as aldehyde, ketone, and α,β-unsaturated ketone. The proposed

• TON of 12125. A mechanistic investigation showed the possible characteristic 31P NMR signals of the amido (126.5 ppm) and alkoxy (at 132.7 and 134.9 ppm) manganese complexes (Scheme 50). C–C Bond formation via alkylation of esters and amides with alcohols Rueping and El-Sepelgy described an exciting

Kinetically stabilized 1,3-diarylisobenzofurans and the possibility of preparing large, persistent isoacenofurans with unusually small HOMO–LUMO gaps

• Qian Liu and
• Glen P. Miller

Beilstein J. Org. Chem. 2024, 20, 1099–1110, doi:10.3762/bjoc.20.97

• switching the dienophile from DMAD to acrylonitrile. Once again, compounds 3 and 23 were unreactive, even after 184 hours of reaction time with a 13,500-fold excess of acrylonitrile. The reaction between 3 and a large excess of DMAD (116 equivalents) in boiling toluene (111 °C) was also studied by 1H NMR

• spectroscopy. After 51 hours of reaction in boiling CH2Cl2, Diels–Alder adduct 27 was observed in 22% yield. Compound 27 was identified by 1H NMR and 13C NMR spectroscopies as well as high-resolution ESI mass spectrometry. Although the lack of reactivity observed for 3 and 23 limited our kinetic analysis, we

• modified cardboard box were utilized for detection of TLC spots. Melting points were determined in open capillary tubes using a Mel-Temp apparatus, and are uncorrected. Proton nuclear magnetic resonance (1H NMR) spectra and carbon nuclear magnetic resonance (13C NMR) spectra were recorded on either a

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• than 90% purity, as determined by 31P NMR. Compound 10 was used in the next step without further purification. A linear amide 11 was obtained in 47% yield by reacting phosphinate 10 with chloroacetamide in the presence of a large excess of HMDS in acetonitrile at 70 °C for two days. A cyclisation of

• in H2O. Removal of toluoyl groups was accomplished in aq NH3, providing pure α- and β-nucleoside of Va and Vc, respectively, carrying a negatively charged phosphinic acid group. These compounds were found to be stable in sodium phosphate buffer at pH 7.0 as no decomposition was observed in NMR

• anomers with a α/β ratio of 2:1, as determined by 1H and 13C NMR. Deprotected nucleosides Va and Vb but not Vc exhibited absorbance in the UV region with ε258 = 4230 L⋅mol−1⋅cm−1 and ε262 = 4730 L⋅mol−1⋅cm−1, respectively. This was most likely a result of the presence of a double bond next to the P=O unit

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• reaction time (4 h overall, entries 3 and 4 in Table 1). In these last experiments a whitish solid appeared during addition of the oxidant, initially observed in the one with lower water amount (Table 1, entry 3). The 1H NMR confirmation of the nature of the solid as 3a, makes clear that phase separation

• undetectable 1H NMR impurities. The application of the same protocol on o-xylene (1, Figure 3) cleanly gave dibromide 1a in almost quantitative yield. Some issues emerged during the isolation step, because of the high lacrimatory activity of 1a [53][54], while 3a lacks the same effect. Higher nucleophilic

• byproducts, that were still detected in small amounts through 1H NMR (see the image in the Supporting Information File 1). Ring bromination of xylenes is commonly carried out using molecular bromine in the absence of light, along with the aforementioned catalytic promoters (FeBr3 or I2) [59][60]. Some

Mild and efficient synthesis and base-promoted rearrangement of novel isoxazolo[4,5-b]pyridines

• Vladislav V. Nikol’skiy,
• Mikhail E. Minyaev,
• Maxim A. Bastrakov and
• Alexey M. Starosotnikov

Beilstein J. Org. Chem. 2024, 20, 1069–1075, doi:10.3762/bjoc.20.94

• inhibitor of homeodomain-interacting protein kinases (HIPKs) [32], and combretastatin A-4 analogs evaluated for their anticancer properties against a panel of 60 human cancer cell lines [33] (Figure 2). The structures of all new compounds were confirmed by 1H and 13C NMR and HRMS. X-ray diffraction studies

• . Yields of compounds 12 and 13. Supporting Information Supporting Information File 16: Experimental section, NMR spectra and X-ray analysis data.

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• -bonding dicyanopyrazinoquinoxaline (DCPQ) suspensions with excess potassium hydroxide, resulting in moderate to good yields. Both families of compounds were analyzed by UV–vis and NMR spectroscopy, where the consequences of hydrogen bonding capability could be assessed through the structure–property

• building blocks 1,2-aceanthrylenedione and 12, as detailed in Table S1 (Supporting Information File 1). However, an inseparable unknown impurity was observed along with the desired product 3a in all cases when analyzed by 1H NMR. Under strict temperature and time control (80 °C for 72 hours) using 2.5

• secured due to the favorable hydrogen bonding (O–H∙∙∙N) between the oxime units; this idea is supported by 1H NMR spectroscopy which shows the presence of two distinct hydroxyl proton signals. The reduction of 7d in the presence of Pd/C and hydrazine monohydrate afforded 1,10-phenanthroline-5,6-diamine

Novel analogues of a nonnucleoside SARS-CoV-2 RdRp inhibitor as potential antivirotics

• Luca Julianna Tóth,
• Kateřina Krejčová,
• Milan Dejmek,
• Eva Žilecká,
• Blanka Klepetářová,
• Lenka Poštová Slavětínská,
• Evžen Bouřa and
• Radim Nencka

Beilstein J. Org. Chem. 2024, 20, 1029–1036, doi:10.3762/bjoc.20.91

• insufficient evidence provided even by meticulous NMR analysis and eventually had to be confirmed by X-ray crystallography (Figure S1, Supporting Information File 1). Changing the ester function from an ethyl to an allyl group enabled a very mild cleavage using a Pd-mediated reaction with triethylsilane [28

Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions

• Naoki Miyamoto,
• Daichi Koseki,
• Kohei Sumida,
• Elghareeb E. Elboray,
• Naoko Takenaga,
• Ravi Kumar and
• Toshifumi Dohi

Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90

• details and copies of 1H, 13C, and 19F NMR spectra. Acknowledgements T.D. thanks for the generous gift of fluoroalcohols from Central Glass Co., Ltd. Funding N.T. and T.D. acknowledge support from JSPS KAKENHI Grant Number 20K06980 (N.T.) and 19K05466 (T.D.), JST CREST grant number JPMJCR20R1 (T.D.), and

A Diels–Alder probe for discovery of natural products containing furan moieties

• Alyssa S. Eggly,
• Namuunzul Otgontseren,
• Carson B. Roberts,
• Amir Y. Alwali,
• Haylie E. Hennigan and
• Elizabeth I. Parkinson

Beilstein J. Org. Chem. 2024, 20, 1001–1010, doi:10.3762/bjoc.20.88

• used, the reaction proceeded well with 78% conversion when monitored by both MS and NMR spectroscopy. However, when sodium chloride was used instead of sodium hydroxide, no conversion was observed. Temperature was also taken into consideration; temperatures above 55 °C were not considered because we

• minimal to no side products were observed via MS or NMR, thus validating the use of starting material for quantification. From this data, a few generalized conclusions can be drawn. Overall, the substrates with higher conversions were 14 and 16, which is in line with our hypothesis that having an electron

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

• determined by 1H NMR spectroscopy (Scheme 15). More recently, in 2016, still in Söderberg’s group, the synthesis of 2,2′-bi-1H-indoles, 2,3′-bi-1H-indoles, 3,3′-bi-1H-indoles, indolo[3,2-b]indoles, and indolo[2,3-b]indoles via reductive cyclization Pd-catalyzed was developed [36]. The reaction was possible

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

• yield. Optimization of reaction conditions. Supporting Information Supporting Information File 8: Experimental procedures, compound characterizations, and NMR spectra. Acknowledgements We acknowledge the contribution from the Ph.D. thesis of co-author Jingyao Li, https://research.rug.nl/en

Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

• Arnaldo G. de Oliveira Jr.,
• Martí F. Wang,
• Rafaela C. Carmona,
• Danilo M. Lustosa,
• Sergei A. Gorbatov and
• Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

• data for the new compounds. Acknowledgements We acknowledge the Ph.D. student Otto Daolio Köster for the fruitful discussions and assistance with the experimental work, and Mr. Anderson S. Pedrosa for technical assistance with NMR analysis. Funding We thank the financial support of the São Paulo

Direct synthesis of acyl fluorides from carboxylic acids using benzothiazolium reagents

• Lilian M. Maas,
• Alex Haswell,
• Rory Hughes and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2024, 20, 921–930, doi:10.3762/bjoc.20.82

• equiv of NaH in DCM under conditions similar to our previous reports on the deoxygenative trifluoromethylthiolation of carboxylic acids [31]. 19F NMR analysis of the crude reaction mixture after 2 h at rt revealed no conversion towards the desired acyl fluoride product 2a, however, 30% of thioester 3a

• was formed (internal standard: PhCF3, Table 1, entry 1). Pleasingly, changing the base to K2CO3 led to the formation of 2a in 7% 19F NMR yield (Table 1, entry 2), while the selectivity of the reaction could be switched significantly upon employing organic amine bases (Table 1, entries 3 and 4). Using

• 2.0 equiv of diisopropylethylamine (DIPEA), 2a could be obtained in quantitative 19F NMR yield although a reduction to 1.5 equiv led to a significant drop in efficiency, delivering the acyl fluoride in only 30% 19F NMR yield together with 45% of thioester 3a (Table 1, entries 4 and 5). At this stage

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

• and 13C NMR, and HRMS analysis. In addition, single crystals of compound 6d and 8c were obtained for X-ray analysis to confirm the structures (Figure 2). Conclusion In conclusion, we have developed a one-pot synthesis with two or three steps for making tetrazolo-pyrazino[2,1-a]isoquinolin-6(5H)-ones

• by NMR. General procedure for the Heck reaction; synthesis of product 6a A mixture of Ugi-azide adduct 5a (1 mmol), Pd(OAc)2 (0.1 mmol), PPh3 (0.2 mmol), K2CO3 (2 mmol) or NaOAc (2 mmol) in MeCN (3 mL) was stirred at 105 °C for 3 h under nitrogen atmosphere. After aqueous work-up, the crude product

• , and copies of NMR spectra. Supporting Information File 31: Crystallographic information file for compound 6d. Supporting Information File 32: Crystallographic information file for compound 8c. Acknowledgements We acknowledge Shaodong Jiang’s early work on this project.

Synthesis and properties of 6-alkynyl-5-aryluracils

• Ruben Manuel Figueira de Abreu,
• Till Brockmann,
• Alexander Villinger,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80

• gives first insights into the optical properties. It was observed that the photophysical properties could be partially modulated by the chosen substituents. Experimental General information Nuclear magnetic resonance spectra (1H/13C/19F NMR) were recorded on a Bruker AVANCE 300 III, 250II, or 500. The

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• oxazolidinone-substituted ynamide also proved to undergo iodo(III)azolation in a regio- and stereoselective fashion to give the product 4ai in a moderate yield. Note that terminal alkynes such as phenylacetylene also took part in the reaction, albeit in a much-diminished yield (7% by 1H NMR; data not shown

Confirmation of the stereochemistry of spiroviolene

• Yao Kong,
• Yuanning Liu,
• Kaibiao Wang,
• Tao Wang,
• Chen Wang,
• Ben Ai,
• Hongli Jia,
• Guohui Pan,
• Min Yin and
• Zhengren Xu

Beilstein J. Org. Chem. 2024, 20, 852–858, doi:10.3762/bjoc.20.77

• to cyclopentane skeleton, as well as its stereochemistry, was originally elucidated as 1' as shown in Figure 1, on the basis of detailed analysis of 1D and 2D NMR spectroscopy. Spiroviolene was also found to be produced by several bacterial strains harboring SvS homologs [6][7], as well as putative

• detailed analysis of the NMR spectra, we have found that besides the normal hydroboration/oxidation product 1α-hydroxyspiroviolane (9), 9α- (10) and 9β-hydroxyspiroviolane (11) resulting from a formal boration at the homoallylic C9 position were also produced. The stereochemistry of the newly generated

• : Materials, synthetic methods, and copies of NMR spectra for all compounds. Supporting Information File 20: Crystallographic information file of compound 13. Funding We are grateful to the National Natural Science Foundation of China (No. 81973197, 81991525, 22107008), Beijing Natural Science Foundation (No

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• reaction was performed in the presence of 10 mol % Cu(OTf)2 and 1.0 equivalent of K2CO3 in DCE at a temperature of 80 °C. To our delight, the reaction afforded 3,4-benzocoumarin 3aa in a 27% yield (Table 1, entry 1). The structure of 3aa was confirmed through NMR spectroscopy and mass spectra analysis

• isolated as stable solids, whose structures were fully characterized by NMR spectroscopy. As shown in Table 3, we utilized 2-naphthol and 1-naphthol as template substrates to react with various unsymmetrical 2-ester-substituted diaryliodonium salts. Remarkably, iodonium salts 2 proved to be versatile in

• and characterization data of all products, copies of 1H, 13C, 19F NMR spectra of all compounds. Acknowledgements The authors thank the Research Center of Analysis and Test of the East China University of Science and Technology for the help on the characterization and Professor Zhen-Jiang Xu from SIOC

Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions

• Martyn Jevric,
• Julian Klepp,
• Johannes Puschnig,
• Oscar Lamb,
• Christopher J. Sumby and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74

• , with the exo-hemiacetals favoured due to steric interactions between the substituents and alcohol, while the attempted preparation of 12b led only to complex mixtures (Scheme 2). The products of the reactions were characterised by 1D and 2D NMR, and X-ray crystallography of members from each class was

• used to confirm assignments. In the 1H NMR spectra of the chlorides 11a–f, a downfield shift for the anomeric methine was observed to δ ≈6 ppm from δ ≈5.4 ppm in the starting materials 10a–f. There was also a characteristic change in the appearance of the oxymethylene bridge spin system, with the

• products exhibiting much larger differences in the chemical shifts for the geminal protons relative to those observed in the starting material. For example, in the 1H NMR spectrum of 11e, the H4/H4′ resonances have a difference of 0.94 ppm, while in 10e, the progenitor H7/H7′ methylene resonances are

Discovery and biosynthesis of bacterial drimane-type sesquiterpenoids from Streptomyces clavuligerus

• Dongxu Zhang,
• Wenyu Du,
• Xingming Pan,
• Xiaoxu Lin,
• Fang-Ru Li,
• Qingling Wang,
• Qian Yang,
• Hui-Min Xu and
• Liao-Bin Dong

Beilstein J. Org. Chem. 2024, 20, 815–822, doi:10.3762/bjoc.20.73

• mainly elucidated through comparative 1H and 13C NMR spectra and by comparing analytical data with existing literature reports [28][29] (see Supporting Information File 1, Figures S1–S7). The 1H NMR spectrum of compound 2 exhibited characteristic signals for one olefinic proton at δH (5.48) and four

• methyl groups at δH (0.83, 0.87, 0.98 and 1.77). Its 13C and DEPT NMR spectra showed 15 carbon resonances, including four methyl groups, four methylenes, four methines, and three quaternary carbon atoms. This information suggests that it may be a drimenol congener and the structure was further supported

• by comparison of analytical data with a literature report [29]. The 1H NMR spectrum of compound 3 is similar to that of 2, showing four methyl groups and one olefinic methyl singlet, indicating structural resemblances with minor variations. It was ultimately determined through literature comparison

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

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

• ) is limited to reactive alkenes but provides very high yields (yields marked with an asterisk are NMR yields). The addition of DCl was also demonstrated by the use of D2SO4 instead of H2SO4. Not surprisingly, as already discussed in section "Reactions with HCl gas", higher pressures of HCl gas gave

• the reactivity of the corresponding alkene towards hydrochlorination. Normal temperature dependence for the hydrochlorination of (Z)-but-2-ene. Pentane slows down the hydrochlorination of 11. Ex situ-generated HCl gas and in situ application for the hydrochlorination of activated alkenes (* = NMR