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 chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

• properties (polarity, solubility) strongly enough to allow easy separation/purification by chromatography and/or recrystallization. The different isomers 178–181 are interesting starting materials in cyclophane chemistry in their own right. Other asymmetrically substituted triple-bond dienophiles that have

Photoreactions of cyclic sulfite esters: Evidence for diradical intermediates

• Rick C. White,
• Benny E. Arney Jr. and
• Heiko Ihmels

Beilstein J. Org. Chem. 2012, 8, 1208–1212, doi:10.3762/bjoc.8.134

• -containing functionalities are rather rare. For instance, the photoextrusion of sulfur dioxide was carried out to facilitate the preparation of cyclophane derivatives [15]. The photochemistry of the corresponding cyclic sulfite esters is even less well known [16][17][18]. A report on the photochemistry of

Control over molecular motion using the cis–trans photoisomerization of the azo group

• Estíbaliz Merino and
• María Ribagorda

Beilstein J. Org. Chem. 2012, 8, 1071–1090, doi:10.3762/bjoc.8.119

• used light intensity [112][113][114]. Molecular threader Stoddart, Balzani et al. [115][116] created an intelligent molecular device (trans-10∙11) capable of moving within a cyclophane 11, as a needle through a buttonhole (Figure 12). The interaction between the two systems is measured on the

• fluorescence emitted by the pyridinium salt free cyclophane. The azobenzene trans-10 is conveniently replaced with electron donor units, so that when it is associated, as azo-10∙11, the fluorescence is completely inhibited by charge-transfer interactions. The photoexcitation carried out by irradiation with

• light of λ = 360 nm of a solution of trans-10 and 11 causes a process of “unthreading”. The cis isomer 10 has a much weaker interaction with cyclophane 11, and this fact is reflected in the large increase in fluorescence intensity of 11. The trans-isomer 10 is regenerated when the mixture is left in the

Use of mixed Li/K metal TMP amide (LiNK chemistry) for the synthesis of [2.2]metacyclophanes

• Marco Blangetti,
• Patricia Fleming and
• Donal F. O'Shea

Beilstein J. Org. Chem. 2011, 7, 1249–1254, doi:10.3762/bjoc.7.145

• [2.2]cyclophane structures and have extensively studied their unusual physical and chemical properties induced by the close spatial proximity of their aryl rings [8]. Undoubtedly the most studied of the series (ortho, meta and para) are the [2.2]paracyclophanes, which have seen a recent resurgence of

• synthesis required identical conditions to the first to provide the di-benzylic metalated derivatives 7 (Table 2). We anticipated that an intramolecular ring closing by oxidative coupling would provide the desired cyclophane product in addition to open chain oligomers or larger ring systems. Substrates 6a–e

• were treated with two equivalents of BuLi/KOt-Bu/TMP(H) to generate the corresponding dianions 7a–e, which upon oxidative coupling gave the corresponding metacyclophanes 8a–e. This provided unsubstituted cyclophane 8a in 40% yield and 5,13-disubstituted derivatives 8b–d, containing CH3, OCH3 and N(CH3

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

• this case the cyclophane moiety is the “order-generating” part of the molecule and the originally flexible, unsaturated chain remain attached to each other by stable C–C-bonds; altogether the process amounts to a stiffening (rigidization) of the molecules 3. In the case of the bis amide 5 (Scheme 2

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides

• Ana Maria Castilla,
• M. Morgan Conn and
• Pablo Ballester

Beilstein J. Org. Chem. 2010, 6, No. 5, doi:10.3762/bjoc.6.5

• stereoselectivity exhibited by the cyclic receptors, together with the lack of selectivity for the size of the amino acid side chain, encourages us to propose that the geometry of the 1:1 complex is, most likely, exo-cyclic. In other words, the dipeptide is not threaded through the cyclophane skeleton of the

[3.3]Dithia-bridged cyclophanes featuring a thienothiophene ring: synthesis, structures and conformational analysis

• Sabir H. Mashraqui,
• Yogesh Sanghvikar,
• Shailesh Ghadhigaonkar,
• Sukeerthi Kumar,
• Auke Meetsma and
• Elise Trân Huu Dâu

Beilstein J. Org. Chem. 2009, 5, No. 74, doi:10.3762/bjoc.5.74

• ], nonlinear optics [22] and axially chiral systems [23]. We have also recently incorporated a thienothiophene ring within the cyclophane framework via its 3,4-positions, leading to the synthesis of meta type 1,3-dithia-bridged thienothiophenophanes 1–2 [24]. Cyclophanes 1–2 (Figure 1) have been found to

• conditions and under N2 atmosphere. The crude solid obtained on work-up was purified by column chromatography on SiO2 affording the desired meta dithia[3.3]cyclophane 7, m.p. 247–250 °C as a colorless solid in 57% yield. Likewise, the para dithia-bridged thienothiophenophanes 9 and 11 were prepared by

• conformational analysis of thienothiophenophanes 7, 9 and 11 The 1H NMR (300 MHz) spectrum of dithia-cyclophane 7 revealed two AB spin systems (4H each) in the range of δ 3.21–4.30 due to the geminal couplings of the bridged –CH2- protons. A singlet centered at δ 2.31 accounted for the C3/C4 methyl groups. The

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

• the cyclophane acting as a convenient scaffold, as demonstrated previously [18][19]. To avoid steric crowding and excessive distance between the chromophores, it seemed reasonable to select the rigid all-trans butadienyl tether as represented in compound 2 (see Figure 3). The synthesis, molecular

• % overall yield as described previously [19]. Therefore, the overall yield of 2 from the parent cyclophane was found tobe 35% on the gram scale. The Wittig reaction provides a mixture of cis and trans isomers, but the pure all-trans isomer was isolated by crystallization as orange crystals (see Experimental

• naphthalenes [21], but because the disubstituted cyclophane also absorbs in that region [22], it is difficult to get more precise information. The 1H NMR (Figure 10 and Supporting Information p S2) and the 13C NMR spectra (52 distinct signals are observed, see Experimental) point to the absence of symmetry in

Enantiospecific synthesis of [2.2]paracyclophane- 4-thiol and derivatives

• Gareth J. Rowlands and
• Richard J. Seacome

Beilstein J. Org. Chem. 2009, 5, No. 9, doi:10.3762/bjoc.5.9

• derivatives [15]. Chiral sulfur [2.2]paracyclophane derivatives are beginning to attract attention due to the great potential such compounds exhibit [16][17][18]. Non-cyclophane-based thiophenol derivatives have been employed in the nucleophilic addition of thioacetals to suitable electrophiles [19][20

Molecular recognition. 1. Crystal structures of hexaazamacrocyclic amines containing p-xylylene spacers and their adducts with acids

• Teresa Borowiak,
• Grzegorz Dutkiewicz,
• Maciej Kubicki,
• Marek Pietraszkiewicz,
• Agnieszka Gil and
• Rainer Mattes

Beilstein J. Org. Chem. 2005, 1, No. 16, doi:10.1186/1860-5397-1-16

• Institute of Inorganic and Analytical Chemistry, University Muenster Corrensstrasse 36, 48149 Muenster, Germany 10.1186/1860-5397-1-16 Abstract The macrocyclic amine, 1,5,9,18,22,26-hexaaza [11.11]-p-cyclophane (1) contains two dipropylenetriamine units which make the molecule highly basic. Owing to this

• efficiency in activation of substrates. This leads to numerous properties as magnetic, electronic or catalytic. [1][3][4][5] In our previous paper we described the supramolecular structures of 1,5,9,18,22,26-hexaaza [11.11]-p-cyclophane (hereafter 1, Scheme 1) complexes with o-nitrophenol and hydrochloric

• secondary amine with a lesser effect produced by the spacer. As the number of methylene units increases, the basicity of the macrocyclic ligands also increases because the amino-groups lie further apart from one another [2] in comparison with 1,4,7,16,19,22-hexaaza [9.9]-p-cyclophane (hereafter 2, Scheme 1