Bi-mediated allylation of aldehydes in [bmim][Br]: a mechanistic investigation

• Mrunesh Koli,
• Sucheta Chatterjee,
• Subrata Chattopadhyay and
• Dibakar Goswami

Beilstein J. Org. Chem. 2018, 14, 2198–2203, doi:10.3762/bjoc.14.193

• solvent systems and room temperature ionic liquids (RTILs) is also ideal for probing in situ formation of different allylmetal species in solution, their stability and reactivity towards electrophiles [8][9][10]. Despite extensive investigation, several key factors of the reaction have not been adequately

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• alkylation of 1,3-dithiole-2-thiones C and E and the corresponding TTF molecules derived from them often in very good yields. An additional strategy to obtain non-symmetrically substituted TTF derivatives is the stepwise reaction of TTF tetrathiolate with different electrophiles [48]. Another important

Cobalt-catalyzed nucleophilic addition of the allylic C(sp³)–H bond of simple alkenes to ketones

• Tsuyoshi Mita,
• Masashi Uchiyama,
• Kenichi Michigami and
• Yoshihiro Sato

Beilstein J. Org. Chem. 2018, 14, 2012–2017, doi:10.3762/bjoc.14.176

• -allylmetal complex that reacts with electrophiles, triggered by allylic C(sp3)–H activation. To this end, Schneider [26], Kanai [27], and we [28][29] reported in 2017 catalytic allylic C(sp3)–H activation of alkenes to react carbonyl electrophiles such as imines, ketones, and CO2 via nucleophilic allylmetal

• allylic C(sp3)–H addition of α-olefins, mainly 1-undecene and their analogues, to ketone electrophiles. Results and Discussion We initially conducted screening of conditions using 1 equiv of 1-undecene (1a) and 3 equiv of acetophenone (2a) as starting materials (Table 1). When the reaction was conducted

• chromatography. It was then purified by silica-gel column chromatography to afford the products 3. Precedent examples of catalytic allylic C(sp3)–H additions to carbonyl electrophiles. Substrate scope for acetophenone derivatives. aPreparative scale synthesis using 1 mmol of 2a. Substrate scope for α-olefins. A

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

• Fateh V. Singh,
• Priyanka B. Kole,
• Saeesh R. Mangaonkar and
• Samata E. Shetgaonkar

Beilstein J. Org. Chem. 2018, 14, 1778–1805, doi:10.3762/bjoc.14.152

• reactions. Hypervalent iodine reagents are mainly popular for their oxidative properties but various iodine(III) reagents have been used as electrophiles. Numerous iodine(III) reagents have been successfully used to achieve diverse spirocyclic scaffolds. Phenols 7 or 11 having an internal nucleophile at

• ortho- or para-position can be used as starting material for the synthesis of ortho- and para-spirocyclic compounds in the presence of iodine(III)-based electrophiles (Scheme 1). Phenolic oxygen of compound 7 attacks to the iodine of 8 to form intermediate 9. Furthermore, on nucleophilic attack of the

• afford spirocyclic compounds 101 in good yields (Scheme 36). Like PIDA and PIFA, Koser reagents are other iodine(III) reagents known to behave as electrophiles. In 2000, Spyroudis and co-workers [109] reported the spirocyclization of para-substituted phenols 102 to corresponding spirocarbocyclic

Glycosylation reactions mediated by hypervalent iodine: application to the synthesis of nucleosides and carbohydrates

• Yuichi Yoshimura,
• Hideaki Wakamatsu,
• Yoshihiro Natori,
• Yukako Saito and
• Noriaki Minakawa

Beilstein J. Org. Chem. 2018, 14, 1595–1618, doi:10.3762/bjoc.14.137

•  7. The reaction of iodosylbenzene and electrophiles, e.g., triflic anhydride or Lewis acids, should generate a potent thiophile 143 that reacts with thioglycoside 144 to form an oxocarbenium ion 145. The resulting oxocarbenium ion 145 should in turn react with a sugar acceptor to give the

Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials

• Alberto Spinella,
• Marco Russo,
• Antonella Di Vincenzo,
• Delia Chillura Martino and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2018, 14, 1498–1507, doi:10.3762/bjoc.14.127

• electrophiles such as epichlorohydrin [6], organic carbonates [7][8][9] or bis-isocyanates [10], in variable ratios depending on the required degree of reticulation. The process, of course, exploits the nucleophilic reactivity of the hydroxy groups of the macrocycle oligosaccharide unit. In general, CyNSs

Three-component coupling of aryl iodides, allenes, and aldehydes catalyzed by a Co/Cr-hybrid catalyst

• Kimihiro Komeyama,
• Shunsuke Sakiyama,
• Kento Iwashita,
• Itaru Osaka and
• Ken Takaki

Beilstein J. Org. Chem. 2018, 14, 1413–1420, doi:10.3762/bjoc.14.118

• organolithium, organomagnesium, organozinc, and organochromium A, to facilitate addition reactions of appropriate carbon electrophiles such as aldehydes (Scheme 1, top) [1]. In contrast, π-electrophilic carbon-connected late transition metals B facilitate the carbometalation of carbon–carbon multiple bonds

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• -diaminocyclohexane moiety from (1R,2R) to (1S,2S) without loss of activity or selectivity. Bifunctional organic molecules combining the thiourea moiety with a tertiary amine functionality are remarkably useful catalysts capable of simultaneous activation of both electrophiles and nucleophiles [51]. Therefore, a

Imide arylation with aryl(TMP)iodonium tosylates

• Souradeep Basu,
• Alexander H. Sandtorv and
• David R. Stuart

Beilstein J. Org. Chem. 2018, 14, 1034–1038, doi:10.3762/bjoc.14.90

• Discussion We initiated our optimization of the arylation of the potassium phthalimide nucleophile with diaryliodonium electrophiles by surveying several reaction conditions: dummy ligand (Aux), counter anion, solvent and volume, reaction temperature, and stoichiometry (Table 1). Consistent with an

• (via Mayr nucleophilicity constants) [16] may be useful in developing other coupling reactions with diaryliodonium electrophiles. Conclusion The coupling of both electron-deficient and sterically encumbered aryl groups with a phthalimide anion is achievable with aryl(TMP)iodonium tosylate salts. This

Cobalt-catalyzed directed C–H alkenylation of pivalophenone N–H imine with alkenyl phosphates

• Wengang Xu and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2018, 14, 709–715, doi:10.3762/bjoc.14.60

• substrates and alkenyl electrophiles would offer a complementary approach for the C–H alkenylation [12]. In particular, C–H alkenylations by way of alkenyl C–O bond cleavage has attracted much attention because of the ready accessibility of the corresponding alkenyl electrophiles (e.g., acetate, phosphate

• ) from ketones [13][14][15][16][17]. Over the last several years, we and others have developed a series of directed arene C–H functionalization reactions with organic electrophiles under low-valent cobalt catalysis [18][19][20][21]. In particular, our group and the Ackermann group have independently

• desired alkenylation product as a colorless oil (43 mg, 88%). Cobalt–NHC-catalyzed C–H alkenylation reactions with alkenyl electrophiles. Reaction of substituted pivalophenone N–H imines with 2a. aThe major regioisomer is shown (rr = regioisomer ratio). Reaction of 1a with various alkenyl phosphates. aA

Copper-catalyzed asymmetric methylation of fluoroalkylated pyruvates with dimethylzinc

• Kohsuke Aikawa,
• Kohei Yabuuchi,
• Kota Torii and
• Koichi Mikami

Beilstein J. Org. Chem. 2018, 14, 576–582, doi:10.3762/bjoc.14.44

• . Herein, we disclose the catalytic asymmetric methylation of trifluoropyruvate derivatives as electrophiles and dimethylzinc as a methylating nucleophile by a chiral copper catalyst. This method is also applicable to the asymmetric synthesis of various α-fluoroalkylated tertiary alcohols bearing CF2H

Addition of dithi(ol)anylium tetrafluoroborates to α,β-unsaturated ketones

• Yu-Chieh Huang,
• An Nguyen,
• Simone Gräßle,
• Sylvia Vanderheiden,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2018, 14, 515–522, doi:10.3762/bjoc.14.37

• substituted with electron-withdrawing groups. Aiming for the systematic investigation of possible steric and electronic influences on the outcome of the reaction, various combinations of electrophiles and nucleophiles were used and the results of the reactions were compared based on the type of the used

• dithioacetal. The scope of the presented procedure is shown with four additional transformations including the use of additional electrophiles and nucleophiles, the use of a chiral auxiliary and subsequent reduction of selected products. Additionally, we extended the reaction to the synthesis of diene

• -dithioacetals [4] are of particular interest as attractive nucleophiles for the addition to halonium ions [5][6], acyl chlorides [7] and other electrophiles [8][9][10] and are broadly used as precursors for [2 + 2]-cycloaddition [11][12], (aza)-Diels–Alder reaction [13][14], and [3 + 2]-cycloaddition reactions

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• positions followed by condensation to electrophiles (Scheme 1). The Reformatsky reagent is usually in situ generated by the treatment of the corresponding α-halocarbonyl compound by a metal in low oxidation state (Zn, Sm, Sn, Cr, In, Ti, Fe, Co, Y, etc.). These robust carbon–carbon bond-forming reactions

• aldehydes as electrophiles [38]. Enantioselectivities of up to 84% ee were achieved by using a BINOL derivative as chiral ligand. Ever since, other types of chiral ligands including chiral Schiff bases [39], bisoxazolidines [40], 1,2-amino alcohols [41], indolinylmethanols [42], and diarylprolinols have

• benzoxathiazine 2,2-dioxides, as electrophiles in the catalytic enantioselective aza-Reformatky reaction [49]. Indeed, these compounds constitute good partners for asymmetric catalysis since they exhibit a rigid structure reducing the conformational mobility and avoiding the E/Z isomerization, thus facilitating

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• –S bonds were developed and already excellently reviewed, including nucleophilic substitution reactions between S-nucleophiles and organic electrophiles, metal-catalyzed C–S bond formations and organocatalytic or enzymatic approaches [15][16][18][20][21][22]. This review provides a brief overview

Conformational preferences of α-fluoroketones may influence their reactivity

• Graham Pattison

Beilstein J. Org. Chem. 2017, 13, 2915–2921, doi:10.3762/bjoc.13.284

• ; Introduction α-Halogenated ketones are widely used electrophiles in organic synthesis, being highly reactive in both nucleophilic addition to the carbonyl group and in SN2 nucleophilic displacements [1]. Our research group has recently been exploring the synthesis and reactivity of α-fluorinated ketones [2][3

• electrophiles available to synthetic chemists for SN2 substitution [5]. The orbital overlap in α-halogenated ketones also provides activation to the carbonyl group, making it more reactive towards nucleophilic addition than non-halogenated carbonyl compounds [6]. However, relatively little work has been

Rh(II)-mediated domino [4 + 1]-annulation of α-cyanothioacetamides using diazoesters: A new entry for the synthesis of multisubstituted thiophenes

• Jury J. Medvedev,
• Ilya V. Efimov,
• Yuri M. Shafran,
• Vitaliy V. Suslonov,
• Vasiliy A. Bakulev and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2017, 13, 2569–2576, doi:10.3762/bjoc.13.253

• photosensitivity and hence could be used in OLED devices [68]. Also these compounds display high nucleophilicity in reactions with electrophiles which are often accompanied by a variety of thiophene heterocycle transformations, and hence could be successfully used for their further functionalization [69

One-pot three-component route for the synthesis of S-trifluoromethyl dithiocarbamates using Togni’s reagent

• Azim Ziyaei Halimehjani,
• Martin Dračínský and
• Petr Beier

Beilstein J. Org. Chem. 2017, 13, 2502–2508, doi:10.3762/bjoc.13.247

• dithiocarbamates via a one-pot reaction of an amine, CS2 and an electrophile is of great interest due to its simplicity and environmental friendly procedure. Diverse electrophiles including alkyl halides [18], epoxides [19], alkenes [20][21][22], aldehydes [23], and alcohols [24] were applied for the synthesis of

Diastereoselective Mannich reactions of pseudo-C₂-symmetric glutarimide with activated imines

• Tatsuya Ishikawa,
• Tomoko Kawasaki-Takasuka,
• Toshio Kubota and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2017, 13, 2473–2477, doi:10.3762/bjoc.13.244

• , Nakanarusawa 4-12-1, Hitachi 316-8511, Japan 10.3762/bjoc.13.244 Abstract As an extension of the boron enolate-based aldol reactions, the oxazolidinone-installed bisimide 1a from 3-(trifluoromethyl)glutaric acid was employed for Mannich reactions with tosylated imines 2 as electrophiles to successfully obtain

• byproduct, 4-toluenesulfonamide (4-MeC6H4SO2NH2) 5 produced by the hydrolysis of the unreacted imines 2 [15]. As expected, aromatic sulfonylimines with electron-withdrawing substituents 2bc–dc acted nicely as electrophiles to furnish the desired adducts 3b–d in high to excellent isolated yields where the

• orbital. In our case, possible electron donation is expected either by the σC-C in TS(pro-R,si) or σC-CF3 in TS(pro-R,re). Because the former orbital is more electron-rich, imines as electrophiles should approach from the si face of the pro-R enolate (E: an appropriate electrophile in Scheme 1). The same

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

• Matthias Wünsch,
• David Schröder,
• Tanja Fröhr,
• Lisa Teichmann,
• Sebastian Hedwig,
• Nils Janson,
• Clara Belu,
• Jasmin Simon,
• Shari Heidemeyer,
• Philipp Holtkamp,
• Jens Rudlof,
• Lennard Klemme,
• Alessa Hinzmann,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2017, 13, 2428–2441, doi:10.3762/bjoc.13.240

• < toluene) have been described to enhance the stability of the transition state, improving the diastereomeric ratio, as well as the reactivity of the nucleophile, resulting in an improved yield [45]. As aldimines have been reported to be rather unreactive electrophiles [53], hard Lewis acids (AlMe3 > AlR3

Synthesis and photophysical properties of novel benzophospholo[3,2-b]indole derivatives

• Mio Matsumura,
• Mizuki Yamada,
• Atsuya Muranaka,
• Misae Kanai,
• Naoki Kakusawa,
• Daisuke Hashizume,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2017, 13, 2304–2309, doi:10.3762/bjoc.13.226

• -fused benzoheteroles containing the group 15 and 16 elements using the ring-closing reaction of dilithium compounds with electrophiles bearing heteroatoms [36]. In continuation of our research, we were interested in the synthesis, molecular structure, and physicochemical properties of the parent

Regiodivergent condensation of 5-alkoxycarbonyl-1H-pyrrol-2,3-diones with cyclic ketazinones en route to spirocyclic scaffolds

• Alexey Yu. Dubovtsev,
• Maksim V. Dmitriev,
• Аndrey N. Maslivets and
• Michael Rubin

Beilstein J. Org. Chem. 2017, 13, 2179–2185, doi:10.3762/bjoc.13.218

• spirocondensation of 5-alkoxycarbonyl-1H-pyrrole-2,3-diones (serving as 1,2-bis-electrophiles) with cyclic ketazinones (serving as either 1,3-C,N- or 1,3-C,O-bis-nucleophiles). Results and Discussion Previously, we demonstrated a convenient approach towards spiro[indole-3,2’-pyrroles] 3 based on catalyst-free

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

• procedure has good potential for application in the fields of organic synthesis, medicinal chemistry and pharmacology. Further work toward expanding this protocol and investigations into the difunctionalization of alkenes with other electrophiles is currently underway in our laboratory, and the results will

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• reactions with different electrophiles (Scheme 1). A lot of different examples for such asymmetric α-functionalization reactions of prochiral nucleophiles under asymmetric chiral cation-based phase-transfer catalysis have been reported so far [9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Besides

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• different olefins. The stilbenes were achieved with high selectivity for trans-products in short reaction time leading to high reaction rates (TOFs of the order of 103) for bromide derivatives. When less reactive electrophiles were used, the catalytic performance depended on the Pd NPs loading. Fundamental

Synthesis and metal binding properties of N-alkylcarboxyspiropyrans

• Alexis Perry and
• Christina J. Kousseff

Beilstein J. Org. Chem. 2017, 13, 1542–1550, doi:10.3762/bjoc.13.154

• -bromocarbonyls such as bromoacetic acid are excellent SN2 electrophiles, and N-alkylation of 2,3,3-trimethylindolenine (1) with bromoacetic acid (2a) was successful, if somewhat sluggish, at room temperature. Reaction of the crude indolium salt 3a with 3-methoxy-5-nitrosalicylaldehyde (5) was also conducted at