β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• . Regioselective epoxide ring opening and 1,2-difunctionalization of alkenes are the commonly employed routes in the synthesis of such compounds. Both strategies are discussed below. 3.1 Synthesis of β-hydroxy sulfides via regioselective ring opening of epoxides The considerable ring strain present in epoxides

• ]-3-oxo-N-o-tolylbutanamides) [61] and S-alkylisothiouronium salts [62]. 3.2 Synthesis of β-hydroxy sulfides via difunctionalization of alkenes Although the synthesis of β-hydroxy sulfides via the thiolysis of epoxides is important, its Achilles’ heel is the need for the preparation of an epoxide

• alkyl radicals than the corresponding diaryl disulfides and benzyl radicals, respectively, are presumed to be the reasons behind the failure of the reaction to work with aliphatic alkenes [67]. 3.3. Synthesis of masked β-hydroxy sulfides via difunctionalization of alkenes Alkenes are versatile

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• of copper(I) iodide as a catalyst for the regioselective difunctionalization of aromatic alkynes and alkenes with an optimal atom-economy (Scheme 4a) [34][35]. The transformation proceeds efficiently, particularly in the presence of an electron-donating substituent on the aromatic ring. The same

• complex. The group of Sodeoka, in parallel, has described the same 1,2-difunctionalization reaction of alkenes and alkynes with 5 in the presence of [Cu(MeCN)4]PF6 as the catalyst (Scheme 5a) [37]. It should be pointed out that this copper(I) complex was previously described by Szabó as a poor catalyst in

• derivatives. This relayed strategy can therefore be applied to non-symmetrical cyclic diaryliodonium species, thereby affording a library of functionalized benzoxazoles 58 with complete regiocontrol. The group of Zhang has developed a one-pot procedure for the sequential difunctionalization of cyclic diaryl

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• electrophilicity and appreciable oxidizing properties. The transformations associated with asymmetric induction mainly focused on the asymmetric oxidation and oxidative dearomatization chemistry. Asymmetric difunctionalization of alkenes, α-functionalization of carbonyls and also some typical 1,2-aryl

• ) reagent 9b was used successively for the synthesis of δ-lactones 45 in a highly stereoselective manner starting from 44 [43]. The formation of cyclic iodonium 46 is the vital part of this difunctionalization process. Wirth et al. were the first to introduce asymmetric dioxytosylation of styrene (47) using

• 52. Fujita et al. further explored the difunctionalization strategy for the development of diacetoxylation of alkenes following a Prevost and Woodward reaction [48]. Recently, the same group used chiral iodine reagent 55 together with acid co-reagent for the intramolecular oxyarylation and

Iodine(III)-mediated halogenations of acyclic monoterpenoids

• Laure Peilleron,
• Tatyana D. Grayfer,
• Joëlle Dubois,
• Robert H. Dodd and
• Kevin Cariou

Beilstein J. Org. Chem. 2018, 14, 1103–1111, doi:10.3762/bjoc.14.96

• more user-friendly protocols that rely on Oxone® [20], DIB [24], or PIFA [25] since the iodide source is an iodide salt and not molecular iodine. Chlorination In the case of chlorination, we have yet to observe adducts arising from the vicinal difunctionalization of the double bond and, in accordance

Chlorination of phenylallene derivatives with 1-chloro-1,2-benziodoxol-3-one: synthesis of vicinal-dichlorides and chlorodienes

• Zhensheng Zhao and
• Graham K. Murphy

Beilstein J. Org. Chem. 2018, 14, 796–802, doi:10.3762/bjoc.14.67

• pathways. For example, Liu and co-workers used Togni’s benziodoxolone reagent [35] in a radical-mediated vicinal 2,3-difunctionalization of allenes, which proceeded via CF3-radical adduct A (Scheme 1a) [36]. In contrast, Muñiz reported that with PhI(NTs2)2, an oxidative amination occurred via cation B

Enantioselective dioxytosylation of styrenes using lactate-based chiral hypervalent iodine(III)

• Morifumi Fujita,
• Koki Miura and
• Takashi Sugimura

Beilstein J. Org. Chem. 2018, 14, 659–663, doi:10.3762/bjoc.14.53

• )-isomer. Keywords: 1,2-difunctionalization of alkenes; enantioselective synthesis; hypervalent iodine; oxidation; Findings Hypervalent aryl-λ3-iodanes have been widely used for metal-free oxidation with high selectivity in organic synthesis [1][2][3]. The reactivity of an aryl-λ3-iodane is controlled by

• for highly stereocontrolled oxidative transformations [4][5][6][7][8][9][10][11][12][13][14]. The enantioselective vicinal difunctionalization of alkenes constitutes one type of attractive transformation achieved by chiral hypervalent iodine compounds. As a seminal example in this field, Wirth et al

• ][28][29], and vicinal difunctionalization of alkenes [18][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. Here, the efficiency of the lactate-based chiral hypervalent iodine reagents 4a–e (Figure 1) was assessed using the dioxytosylation of styrenes as a reference

Difunctionalization of alkenes with iodine and tert-butyl hydroperoxide (TBHP) at room temperature for the synthesis of 1-(tert-butylperoxy)-2-iodoethanes

• Hao Wang,
• Cui Chen,
• Weibing Liu and
• Zhibo Zhu

Beilstein J. Org. Chem. 2017, 13, 2023–2027, doi:10.3762/bjoc.13.200

• , Maoming 525000, P. R. China. Fax: +86-668-2923575; Tel: +86-668-2923956 10.3762/bjoc.13.200 Abstract We developed a direct vicinal difunctionalization of alkenes with iodine and TBHP at room temperature. This iodination and peroxidation in a one-pot synthesis produces 1-(tert-butylperoxy)-2-iodoethanes

• applications and allow further chemical modifications, enabling the preparation of synthetically valuable molecules. Keywords: difunctionalization of alkenesiodine; iodination–peroxidation reaction; TBHP; Introduction Alkenes have attracted considerable interest in recent years as abundant, simple chemical

• feedstocks and organic molecules, owing to their potential for extensive application in organic syntheses. Approaches for the efficient, regio- and chemoselective difunctionalization of alkenes have been developed that are attractive for rapidly building complex difunctionalized molecules from simple

Cascade alkylarylation of substituted N-allylbenzamides for the construction of dihydroisoquinolin-1(2H)-ones and isoquinoline-1,3(2H,4H)-diones

• Ping Qian,
• Bingnan Du,
• Wei Jiao,
• Haibo Mei,
• Jianlin Han and
• Yi Pan

Beilstein J. Org. Chem. 2016, 12, 301–308, doi:10.3762/bjoc.12.32

• mixture was charged onto silica gel and purified by flash chromatography to furnish the corresponding products 5 and 7. Cascade 1,2-difunctionalization and cyclization to construct heterocycles. Cyclization of cyclohexane (2a) with substituted N-(2-methylallyl)benzamide (reaction conditions: 4 (0.2 mmol

Copper-catalyzed intermolecular oxyamination of olefins using carboxylic acids and O-benzoylhydroxylamines

• Brett N. Hemric and
• Qiu Wang

Beilstein J. Org. Chem. 2016, 12, 22–28, doi:10.3762/bjoc.12.4

• -benzoylhydroxylamines as an electrophilic amine source and carboxylic acids as a nucleophilic oxygen source to achieve a modular difunctionalization of olefins. The reaction proceeded in a regioselective manner with moderate to good yields, exhibiting a broad scope of carboxylic acid, amine, and olefin substrates

• Liu reported a palladium-catalyzed introduction of phthalimide (HNPhth) and acetate functionalities to terminal allylic and homoallylic ethers in the presence of an iodine oxidant (Scheme 1B) [13]. The Yoon lab also developed copper- and iron-catalyzed olefin difunctionalization reactions with

• transformation, integrating an electrophilic amination with a nucleophilic oxygenation, builds upon our recent development in copper-catalyzed olefin difunctionalization, such as copper-catalyzed diamination [40] and amino lactonization [34]. This strategy overcomes common issues of chemo- and regioselectivity

C–H bond halogenation catalyzed or mediated by copper: an overview

• Wenyan Hao and
• Yunyun Liu

Beilstein J. Org. Chem. 2015, 11, 2132–2144, doi:10.3762/bjoc.11.230

• ]. Halogenation of the alkene C(sp2)–H bond Beside the arene C–H bond, the alkene C–H is another typical C(sp2)–H bond. However, unlike the arene C–H bond, the alkene C–H bond tends to undertake difunctionalization via the cleavage of the π-bond in the presence of halogen source. Therefore, the halogenation of

Switching the reaction pathways of electrochemically generated β-haloalkoxysulfonium ions – synthesis of halohydrins and epoxides

• Akihiro Shimizu,
• Ryutaro Hayashi,
• Yosuke Ashikari,
• Toshiki Nokami and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2015, 11, 242–248, doi:10.3762/bjoc.11.27

• . Keywords: DMSO; electrosynthesis; epoxides; halohydrins; halogen cations; Introduction Alkene difunctionalization through three-membered ring halonium ion intermediates [1] is an important transformation in organic synthesis. Usually the halonium ions such as bromonium or iodonium ions are generated by

• . Recently, we reported that dimethyl sulfoxide (DMSO) can also be used to effectively stabilize halogen cations (Scheme 1) [22]. The pools of stabilized halogen cations enable alkene difunctionalization. We previously reported that the reaction of alkenes with DMSO-stabilized halogen cations such as Br+ and

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

• reported that visible-light-induced photoredox catalysis could serve as a more environmental-friendly alternative reaction system to obtain Br2 in situ from CBr4, an oxidative quencher of photoredox catalyst [16][17][18][19][20][21][22]. Thus, as part of difunctionalization of alkenes, with our continuous

A reductive coupling strategy towards ripostatin A

• Kristin D. Schleicher and
• Timothy F. Jamison

Beilstein J. Org. Chem. 2013, 9, 1533–1550, doi:10.3762/bjoc.9.175

• substitution patterns [12][13][14][15]. Most recently, Sigman and colleagues have reported a palladium-catalyzed 1,4-difunctionalization of 1,4-butadiene with vinylboronic acid and vinyl triflate that can be used to rapidly access the skipped triene of ripostatin A [16]. We recognized that the C11 stereocenter

Homolytic substitution at phosphorus for C–P bond formation in organic synthesis

• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 1269–1277, doi:10.3762/bjoc.9.143

• phosphorus always culminates in difunctionalization of a multiple bond. Therefore this methodology will find application in the synthesis of complex phosphines including bidentate ones. Radical substitution of halogen in organic halide with phosphorus will be an alternative to classical ionic substitution

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

• Kei Murakami and
• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 278–302, doi:10.3762/bjoc.9.34

• ). The versatile 1,4-migration reactions were widely applicable for the 1,2-difunctionalization of arenes. In 2012, Gosmini reported similar cobalt-catalyzed arylzincation reactions of alkynes, which provided tri- or tetrasubstituted alkenes with high stereoselectivity [117]. Their catalytic system was

Alkoxide-induced ring opening of bicyclic 2-vinylcyclobutanones: A convenient synthesis of 2-vinyl-substituted 3-cycloalkene-1-carboxylic acid esters

• Xiufang Ji,
• Zhiming Li,
• Quanrui Wang and
• Andreas Goeke

Beilstein J. Org. Chem. 2012, 8, 650–657, doi:10.3762/bjoc.8.72

• [18][19][20][21][22][23]. Ring-opening reactions of cyclobutanones are expected to be a valuable methodology for vicinal difunctionalization of double bonds. A prerequisite for this reaction to take place is the presence at C-2 of substituents capable of stabilizing the developing vicinal carbanion [6