Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• -phenylthiazoline (87) in 2015 in addition to the synthesis of 5-bromomethtyl-2-thiazoline (Scheme 41), using sulfur as an internal nucleophile (Scheme 48) [48]. Using PhI(OAc)2 with TMSI, N-allylbenzothioamide (78) was cyclised to form 87 in excellent yield. Conclusion The HVI-mediated halocyclization of alkenes

Chiral bifunctional sulfide-catalyzed enantioselective bromolactonizations of α- and β-substituted 5-hexenoic acids

• Sao Sumida,
• Ken Okuno,
• Taiki Mori,
• Yasuaki Furuya and
• Seiji Shirakawa

Beilstein J. Org. Chem. 2024, 20, 1794–1799, doi:10.3762/bjoc.20.158

• optical purity. Conclusion In summary, our BINOL-derived chiral bifunctional sulfide-catalyzed enantioselective halocyclization technology was successfully applied to the catalytic asymmetric bromolactonization of α- and β-substituted 5-hexenoic acids. The target optically active δ-valerolactone products

Synthesis of medium and large phostams, phostones, and phostines

• Jiaxi Xu

Beilstein J. Org. Chem. 2023, 19, 687–699, doi:10.3762/bjoc.19.50

• and NaCl. Only one example was reported for this class of the synthesis via C–C bond formation (Scheme 10) [30]. 1.2 Synthesis via C–O bond formation Halocyclization has been widely applied in the syntheses of phostone and phostine derivatives via C–O bond formation [13][17]. Both bromo and iodo

• (biscollidine) hexafluorophosphates were efficient halogenium reagents in the electrophilic halocyclization. Hydrogen methyl hex-5-en-1-ylphosphonate (49) generated 2-methoxy-7-iodomethyl-1,2-oxaphosphepane 2-oxide (50a) in 65% yield in 62:38 diastereomeric ratio with iodo(biscollidine) hexafluorophosphate as

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• -disubstituted-α-hydroxy-carboxylamides, was disclosed by Gulder and co-workers [76]. This catalytic system was applied to the bromination of alkenes by Gulder and co-workers. For example, the iodine(III)-catalyzed halocyclization of methacrylamide 68 generated the brominated oxindole 69 (Scheme 20) [77]. In

Hypervalent iodine-mediated Ritter-type amidation of terminal alkenes: The synthesis of isoxazoline and pyrazoline cores

• Sang Won Park,
• Soong-Hyun Kim,
• Jaeyoung Song,
• Ga Young Park,
• Darong Kim,
• Tae-Gyu Nam and
• Ki Bum Hong

Beilstein J. Org. Chem. 2018, 14, 1028–1033, doi:10.3762/bjoc.14.89

• , diverse halonium sources have been utilized for the synthesis of isoxazolines via halocyclization. Furthermore, transition metal-, visible light, and hypervalent iodine-mediated oxidative cyclization protocols provide isoxazoline backbones bearing diverse substituents such as –SR, -CF3, -OH and halogens

One-pot preparation of 4-aryl-3-bromocoumarins from 4-aryl-2-propynoic acids with diaryliodonium salts, TBAB, and Na₂S₂O₈

• Teppei Sasaki,
• Katsuhiko Moriyama and
• Hideo Togo

Beilstein J. Org. Chem. 2018, 14, 345–353, doi:10.3762/bjoc.14.22

• 3Aa or 3Aa’, the halocyclization of 2Aa with N-bromosuccinimide (NBS, 2.0 equiv)/BF3·Et2O (1.1 equiv), with 1,3-diiodo-5,5-dimethylhydantoin (DIH, 2.0 equiv)/BF3·Et2O (1.1 equiv), and with 1,3-dibromo-5,5-dimethylhydantoin (DBH, 2.0 equiv)/BF3·Et2O (1.1 equiv) was carried out to form 3-bromo-4

• preparation of 3-bromo-4-phenylcoumarins 3a from 3-phenyl-2-propynoic acid (1a) with daryliodonium triflates B–E. Derivatization of 3-bromo-4-phenylcoumarin. Possible reaction pathway. O-Phenylation of 3-phenyl-2-propynoic acid (1a) with diphenyliodonium triflate (A). Halocyclization of phenyl 3-phenyl-2

N-Propargylamines: versatile building blocks in the construction of thiazole cores

• S. Arshadi,
• E. Vessally,
• L. Edjlali,
• R. Hosseinzadeh-Khanmiri and
• E. Ghorbani-Kalhor

Beilstein J. Org. Chem. 2017, 13, 625–638, doi:10.3762/bjoc.13.61

• examples are collected in Table 1 [87]. Recently, to develop an efficient protocol for the synthesis of 5-(iodomethylene)-3-methylthiazolidines 27 from N-propargylamines, X. Zhou and co-workers have investigated the three-component halocyclization of N-propargylamines 25, aryl isothiocyanates 26, and

• -propargylthioamide intermediate A. Synthesis of 5-(dibromomethyl)thiazoles 44 via halocyclization of N-propargylamines 43 described by Yarovenko. Synthesis of dihydrothiazoles 46 through the treatment of N-propargylamides 45 with Lawesson’s reagent. Synthesis of thiazoles 49 by treatment of silyl-protected N

Intermolecular addition reactions of N-alkyl-N-chlorosulfonamides to unsaturated compounds

• Gerold Heuger and
• Richard Göttlich

Beilstein J. Org. Chem. 2015, 11, 1226–1234, doi:10.3762/bjoc.11.136

• halonium ions in a halocyclization [40] (Scheme 6). We only obtained the simple addition product 16 with no traces of halocyclization, again ruling out a polar pathway. Conclusion In summary we have shown that N-chlorosulfonamides can be added to styrenes efficiently under copper(I) catalysis via amidyl

• -chlorosulfonamides. Proposed mechanism of the chlorination. Ring opening in the case of cationic or radical intermediates. Addition to unsaturated alcohols prone to halocyclization. Optimized addition reactions of 2a with styrene. Addition reactions of 2a with styrene derivatives. Addition reactions of 2a with

Visible-light-induced bromoetherification of alkenols for the synthesis of β-bromotetrahydrofurans and -tetrahydropyrans

• Run Lin,
• Hongnan Sun,
• Chao Yang,
• Youdong Yang,
• Xinxin Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2015, 11, 31–36, doi:10.3762/bjoc.11.5

• . Keywords: alkenols; bromoetherification; photoredox catalysis; visible light; Introduction The halocyclization of alkenes provides an excellent synthetic method for halogenated heterocycles [1][2][3]. In recent years, haloaminocyclization [4][5], halolactonization [6][7] and haloetherification [8][9] of

Synthesis of diverse indole libraries on polystyrene resin – Scope and limitations of an organometallic reaction on solid supports

• Kerstin Knepper,
• Sylvia Vanderheiden and
• Stefan Bräse

Beilstein J. Org. Chem. 2012, 8, 1191–1199, doi:10.3762/bjoc.8.132

• ], palladium-catalyzed indole synthesis [34][35][36][37][38][39][40], cycloaddition strategies [41], C-arylation of substituted acetonitriles or 1,3-dicarbonyl compounds [42], halocyclization [43][44] and finally, reduction of ortho-fluoro-nitroarenes [42]. The significant biological properties and the

Combined directed ortho-zincation and palladium-catalyzed strategies: Synthesis of 4,n-dimethoxy-substituted benzo[b]furans

• Verónica Guilarte,
• M. Pilar Castroviejo,
• Estela Álvarez and
• Roberto Sanz

Beilstein J. Org. Chem. 2011, 7, 1255–1260, doi:10.3762/bjoc.7.146

• 2,3-difunctionalized phenol derivatives were applied to the synthesis of 4-functionalized benzo[b]furans [39], 4- or 7-alkoxyindoles [40], and 7-oxy-substituted benzo[b]thiophenes [41] by employing Pd-catalyzed cross-coupling reactions or halocyclization processes. Following our interest in the

When gold can do what iodine cannot do: A critical comparison

• Sara Hummel and
• Stefan F. Kirsch

Beilstein J. Org. Chem. 2011, 7, 847–859, doi:10.3762/bjoc.7.97

• , although all ligands tested with the gold complexes and silver salt AgSbF6 allowed full conversion to the indene. From these results, Sanz and co-workers also reported the corresponding halocyclization of o-alkynylstyrenes to yield 3-halo-1H-indenes by employing NIS as the iodonium source (Scheme 7b) [92

• ]. This reaction proceeds via an exceptional 5-endo halocyclization, which likely results from the stability of the tertiary carbocation, since only H at the C1-position rendered the enyne unreactive under the conditions used (excess NIS, CH2Cl2 at reflux). From a synthetic point of view, the development

• of an asymmetric halocyclization towards indenes remains an ongoing task [93][94][95][96]. Notably, 1,5-enynes that do not contain an aryl system react in quite a similar manner when disubstituted at C1. For example, Michelet and co-workers reported the diastereoselective cycloisomerization of 1,5

Phase- vanishing halolactonization of neat substrates

• Nicole Windmon and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2008, 4, No. 29, doi:10.3762/bjoc.4.29

• ; halocyclization; halolactonization; iodine monochloride; phase-vanishing reactions; Introduction Phase-vanishing reactions, introduced by Ryu [1], Curran [1][2] and Verkade [3], are triphasic reactions, which involve a reagent, a substrate and a liquid perfluoroalkane. A more recent improvement of phase