Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• , dibromide 83 was converted to bis-aldehyde 84. Finally, McMurry coupling of dialdehyde 84 provided the cyclophane derivative 85 (28%). Yamoto and co-workers have reported the synthesis of medium-sized cyclophanes, [2.n]metacyclophane-1,2-diols 86 and 87 by using the McMurry coupling as a key step (Figure 8

• -ol (110) generates the diyne product in quantitative yield. Next, the in situ prepared diyne was subjected to hydrogenation followed by oxidation with PCC which gave the dialdehyde 111 (85%). The pinacol coupling of the dialdehyde 111 in the presence of Sm2+ and HMPA generated the cyclophane 112 in a

• moderate yield. RCM of the diene derived from the dialdehyde 111 afforded the macrocyclic cyclophane 113 as a less strained product (Scheme 16). Sonogashira coupling: Wegner and co-workers [125] have reported the synthesis of cyclophanes 122a–c via Sonogoshira coupling [126] (Scheme 17). To this end, the

A hybrid electron donor comprising cyclopentadithiophene and dithiafulvenyl for dye-sensitized solar cells

• Gleb Sorohhov,
• Chenyi Yi,
• Michael Grätzel,
• Silvio Decurtins and
• Shi-Xia Liu

Beilstein J. Org. Chem. 2015, 11, 1052–1059, doi:10.3762/bjoc.11.118

• [20] of 4,5-bis(hexylthio)-1,3-dithiole-2-thione with the dialdehyde CPDT 3 [21] was successfully applied. The preparation of the latter was accomplished in 57% yield through the reaction of 4,4-dihexyl-4H-cyclopenta[2,1-b:3,4-b’]dithiophene [22] with oxalyl chloride in the presence of DMF. However

Novel stereocontrolled syntheses of tashiromine and epitashiromine

• Loránd Kiss,
• Enikő Forró and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2015, 11, 596–603, doi:10.3762/bjoc.11.66

• dialdehyde intermediates has been efficiently applied in recent years for the synthesis of a series of valuable organic molecules [45][46][47][48][49][50][51][52]. In particular, Davies and co-workers have utilized the oxidative ring opening of cyclic vicinal diols followed by ring closure for access to

• stereoisomers (determined on the basis of 1H NMR data) failed, but the mixture could be applied in the next ring-opening oxidation step, since it gave only one open-chain diformyl intermediate I2. Similarly to the cis isomer, this unstable dialdehyde intermediate was subjected without isolation to catalytic

Building complex carbon skeletons with ethynyl[2.2]paracyclophanes

• Ina Dix,
• Lidija Bondarenko,
• Peter G. Jones,
• Thomas Oeser and
• Henning Hopf

Beilstein J. Org. Chem. 2014, 10, 2013–2020, doi:10.3762/bjoc.10.209

• as a side-product together with the dimer of the substrate, dialdehyde 17. Although these two compounds could be separated on a small scale for analytical purposes (see data in Supporting Information File 1) by extensive column chromatography, for further transformations a 16/17 mixture was employed

Synthesis of a bifunctional cytidine derivative and its conjugation to RNA for in vitro selection of a cytidine deaminase ribozyme

• Nico Rublack and
• Sabine Müller

Beilstein J. Org. Chem. 2014, 10, 1906–1913, doi:10.3762/bjoc.10.198

• properties of the RNA's 3'-terminal cis-diol, which can be specifically oxidized with metaperiodate [26][27][28], followed by reaction of the produced dialdehyde with amines or hydrazines linked to a desired functional entity [29]. We set out to select from a random library catalytically active RNAs that

• a biotin was introduced. Upon periodate oxidation of the 3'-cis diol of the RNA library molecules, the produced dialdehyde is thought to react with the primary amino group of the cytidine derivative allowing immobilization of the resulting modified RNAs onto a solid surface through biotin

• GAU CCG UG) corresponding to the 3'-terminal sequence of the envisaged RNA-library. The RNA was oxidized by treatment with sodium periodate [42], and the resulting dialdehyde was reacted with cytidine derivative 1. The obtained intermediate was reduced with sodium cyanoborohydride to form the more

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

The Flögel-three-component reaction with dicarboxylic acids – an approach to bis(β-alkoxy-β-ketoenamides) for the synthesis of complex pyridine and pyrimidine derivatives

• Mrinal K. Bera,
• Moisés Domínguez,
• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 394–404, doi:10.3762/bjoc.10.37

• method in order to finally prepare a macrocyclic compound such as 34 (Scheme 7). Treatment of 23a with an excess of selenium dioxide at 90 °C resulted in the formation of an inseparable mixture of two different aldehydes (probably the dialdehyde and the monoaldehyde). After reduction of the mixture with

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• quarternary carbon center, the resulting amide cyclized during the purification on silica to give amide 174. Reduction of this amide to the aminal was followed by dehydration and Lemieux–Johnson [149] oxidative cleavage to give dialdehyde 175. The liberated alcohol moiety was reprotected, followed by cleavage

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

Intraannular photoreactions in pseudo-geminally substituted [2.2]paracyclophanes

• Henning Hopf,
• Vitaly Raev and
• Peter G. Jones

Beilstein J. Org. Chem. 2011, 7, 658–667, doi:10.3762/bjoc.7.78

• any detectable photoproducts. The success in preparing cyclobutane derivative 4 (n = 1) from the corresponding cinnamophane diester 3 (n = 1, quantitative yield) led us to attempt to prepare the corresponding cyclobutane dialdehyde derivative 16 (Scheme 6). Unfortunately, although this was the only

Preparation and NMR spectra of four isomeric diformyl[2.2]paracyclophanes (cyclophanes 66)

• Ina Dix,
• Henning Hopf,
• Thota B. N. Satyanarayana and
• Ludger Ernst

Beilstein J. Org. Chem. 2010, 6, 932–937, doi:10.3762/bjoc.6.104

• four different modes (Scheme 1) [2]. Depending on the amounts and the quality of the solutions containing the tetraene 1 and the dienophile 2, more than 60 g of the dialdehyde mixture 4 can be obtained in a single run, corresponding to maximum yields of 46%. Both starting compounds are very reactive

Ring strain and total syntheses of modified macrocycles of the isoplagiochin type

• Andreas Speicher,
• Timo Backes,
• Kerstin Hesidens and
• Jürgen Kolz

Beilstein J. Org. Chem. 2009, 5, No. 71, doi:10.3762/bjoc.5.71

• of isoplagiochin C (1), however failed in this case. This might be due to the enhanced ring strain. Since the McMurry reaction would provide more rigorous conditions for the formation of ring-strained frameworks, the hydroxyaldehyde 27 was oxidized to the dialdehyde 28. It is worth mentioning that 28

• was obligatory to prevent exclusive pinacolborane reduction. ddppf: 1,1′-bis(diphenylphosphino)ferrocene. Synthesis of the tolane precursors 27 and 28 for cyclization. Synthesis of the modified macrocycles 5–7 from the dialdehyde precursors 28–30. Synthesis of the known macrocycle 3 via McMurry

Reversible intramolecular photocycloaddition of a bis(9-anthrylbutadienyl)paracyclophane – an inverse photochromic system. (Photoactive cyclophanes 5)

• Henning Hopf,
• Christian Beck,
• Jean-Pierre Desvergne,
• Henri Bouas-Laurent,
• Peter G. Jones and
• Ludger Ernst

Beilstein J. Org. Chem. 2009, 5, No. 20, doi:10.3762/bjoc.5.20

• structure and photochromic properties of 2 are reported in this paper. Results and Discussion 1 Synthesis Compound 2 was prepared from dialdehyde 3 using the Wittig reaction, as outlined in Scheme 1, in 48% yield. Dialdehyde 3 wasobtained in five steps from [2.2]paracylophane, a commercial product, in 72

• of oxygen with an argon or nitrogen stream. Preparations 1. 4,13-bis[(1E,3E)-4-(9-anthracenyl)-buta-1,3-dienyl][2.2]paracyclophane (2): In a 250 mL, dried round-bottom flask, equipped with a reflux condenser, a Claisen adapter, a stirring system, and degassed with nitrogen, 1.3 g dialdehyde (4.1 mmol

• dialdehyde solution and the reaction medium was stirred overnight at ambient temperature. Finally, the reaction mixture was hydrolyzed with crushed ice/water. The crude product was filtered off, dissolved in a small volume of CH2Cl2 and dried over MgSO4. After adding 3 g of silica gel to the filtered

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

• ) (ED50 <10−12 µg/mL compared to adriamycin, ED50 = 1.76 × 10−2 µg/mL) [78][81]. In 1997, Marshall’s group reported the total synthesis of asiminocin (198) through a bidirectional approach starting from the (S,S)-tartrate derived dialdehyde 200 and the (R)-α-OSEM stannane 199 (Scheme 27) [82]. Addition of

• employed the (R)-α-OSEM allylic stannane 261 reaction with the dialdehyde 262 obtained from (S,S)-diethyl tartrate to afford the bis-adduct 263 (Scheme 36). Treatment of 263 with TBAF led to the core bis-THF intermediate, diol 264. Mono tosylation and subsequent hydrogenolysis with LiBEt3H gave alcohol 265

Sordarin, an antifungal agent with a unique mode of action

• Huan Liang

Beilstein J. Org. Chem. 2008, 4, No. 31, doi:10.3762/bjoc.4.31

• and electronic constraints (Scheme 11). Selective Lemieux-Johnson cleavage of the vinyl groups using OsO4 and NaIO4 in the presence of PhB(OH)2 [33] afforded the dialdehyde 54. Racemic sordaricin (2) was completed after a few standard redox and protective group manipulations. The synthesis of

Combining two-directional synthesis and tandem reactions, part 11: second generation syntheses of (±)-hippodamine and (±)-epi-hippodamine

• Annabella F. Newton,
• Martin Rejzek,
• Marie-Lyne Alcaraz and
• Robert A. Stockman

Beilstein J. Org. Chem. 2008, 4, No. 4, doi:10.1186/1860-5397-4-4

• sensitive dialdehyde 5 . Whilst we were able to purify compound 5, this resulted in a significant loss of material through degradation of the dialdehyde on the purification media, be it silica gel or neutral alumina. Thus, we found that use of the crude dialdehyde in the subsequent Horner-Wadsworth-Emmons

• immediately after isolation of the dialdehyde 5 (this was found to decompose upon storage, even at low temperature), and also the oxidative cleavage reaction produced large amounts of toxic osmium waste. During our recent synthesis of histrionicotoxin [11], we found that two-directional homologation of a

Trapping evidence for the thermal cyclization of di-(o-acetylphenyl)acetylene to 3,3'-dimethyl- 1,1'-biisobenzofuran

• Charles P. Casey,
• Neil A. Strotman and
• Ilia A. Guzei

Beilstein J. Org. Chem. 2005, 1, No. 18, doi:10.1186/1860-5397-1-18

• reactions with oxygen, either in the presence or absence of light, to give diketones as the predominant products.[4][5][6][7] The bicyclization process considered for the conversion of 1 to A is analogous to the thermal rearrangement of a 2,6-alkadien-4-yn-1,8-dialdehyde to a bifuran observed by Iyoda[8

• rearrangement of a 2,6-alkadien-4-yn-1,8-dialdehyde to a bifuran. Photochemical cyclization to a bifuran. Trapping of A by DMAD to form Diels-Alder adducts meso-3 and rac-3. Possible stepwise mechanism for rearrangement of 1 to A. Possible concerted mechanism for rearrangement of 1 to A. Ring closures of o-acyl