Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• substitution for the minimization of 1,3-allylic strain to enable Suzuki coupling for biaryl formation as a single atropisomer. The optimized conditions for this transformation utilize Buchwald’s catalyst (SPhos and Pd-based G2 precatalyst) in conjunction with K3PO4. With DBCOD bearing carboxylic acid handles

A Streptomyces P450 enzyme dimerizes isoflavones from plants

• Run-Zhou Liu,
• Shanchong Chen and
• Lihan Zhang

Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113

• and 2 with respect to atropisomerism was assessed by chiral HPLC analysis and the comparison of experimental and calculated ECD spectra. While 1 showed a ≈3:1 atropisomer ratio, with the M-atropisomer being the major form, 2 did not exhibit a Cotton effect in the ECD measurement, suggesting that it is

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

• Alemayehu Gashaw Woldegiorgis and
• Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

• nucleophilic addition to afford axially chiral aryl-alkene-indole frameworks (89) in up to 98% yield, >95:5 E/Z, and up to 97% enantioselectivity (Scheme 30). The nonbiaryl N–C atropisomer is an important structural scaffold, which is present in natural products, medicines. and chiral ligands due to the

A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

• Shun Saito,
• Kota Atsumi,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Naoya Oku,
• Md. Rokon Ul Karim,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97

• effects at 236 nm and 217 nm, respectively, which was consistent with a Cotton effect pattern predicted for the Sa-atropisomer of 1b. Moreover, the overall spectral feature of the experimental and calculated ECDs were quite similar with each other (Figure 5). Based on these results, the absolute

Self-assembled coordination thioether silver(I) macrocyclic complexes for homogeneous catalysis

• Zhen Cao,
• Aline Lacoudre,
• Cybille Rossy and
• Brigitte Bibal

Beilstein J. Org. Chem. 2019, 15, 2465–2472, doi:10.3762/bjoc.15.239

• -atropisomer, as revealed by X-ray diffraction. This alkylaryl thioether ligand (L) formed different macrocyclic complexes by coordination with silver(I) salts depending on the nature of the anion: M2L2 for AgOTf and AgOTFA, M6L4 for AgNO3. A discrete M2L complex was obtained in the presence of bulky PPh3AgOTf

• candidates for directional metal coordination. Herein, a new syn-atropisomer of 9,10-DPA ortho-substituted by two thioethers is exploited as a ligand for silver(I) salts. The impact of this bis-thioether ligand on silver(I) homogeneous catalysis is evaluated in two tandem addition/cycloisomerization

• the stoichiometry of coordination complexes. Atropisomer 1 directed the self-assembly towards the same half-space (regarding the anthracene core). The triflate anion lead to a [2 + 2] macrocycle meanwhile the more coordinating nitrate anion induced the formation of a large globular macrocycle M6L4. A

Synthesis and biological evaluation of truncated derivatives of abyssomicin C as antibacterial agents

• Leticia Monjas,
• Peter Fodran,
• Johanna Kollback,
• Carlo Cassani,
• Thomas Olsson,
• Maja Genheden,
• D. G. Joakim Larsson and
• Carl-Johan Wallentin

Beilstein J. Org. Chem. 2019, 15, 1468–1474, doi:10.3762/bjoc.15.147

• activity, several synthetic studies [11][12][13][14], formal [15] and total [7][8][9][16][17] syntheses of AbC and its slightly more active atropisomer (atrop-AbC) have been reported in the last ten years. Due to its complex structure, these total syntheses are long and thus not compatible with further

Catalytic asymmetric oxo-Diels–Alder reactions with chiral atropisomeric biphenyl diols

• Chi-Tung Yeung,
• Wesley Ting Kwok Chan,
• Wai-Sum Lo,
• Ga-Lai Law and
• Wing-Tak Wong

Beilstein J. Org. Chem. 2019, 15, 955–962, doi:10.3762/bjoc.15.92

• the reactivity and selectivity (5 and 6). Recently, we found that compound 5, which can form a pair of atropisomer (P)-(R,R)-5 and (M)-(R,R)-5, gave different results in N-nitroso aldol reactions compared to 1 [38]. Results and Discussion Synthetic procedures Synthetic steps of catalyst 3 were similar

• Information File 1). Homo-coupling of (S)-b with Ni(COD)2 was achieved with very high diastereoselectivity and only a single atropisomer was formed. The X-ray crystal structure showed that it is (M)-(S,S)-3 (Figure 1). This high atropstereoselectivity is believed to be due to the energetically unfavorable

• formation of the other atropisomer (P)-(S,S)-3 as a higher steric repulsion is generated during the close approach of two bulky phenyl peripheral substituents. The X-ray crystal structure also reveals that an alternative formation of intra- and intermolecular hydrogen bonds [intra- D(OH···O): 1.951(3) Å

Some mechanistic aspects regarding the Suzuki–Miyaura reaction between selected ortho-substituted phenylboronic acids and 3,4,5-tribromo-2,6-dimethylpyridine

• Piotr Pomarański,
• Piotr Roszkowski,
• Jan K. Maurin,
• Armand Budzianowski and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2018, 14, 2384–2393, doi:10.3762/bjoc.14.214

• spectroscopy and X-ray crystallography (Figure 1) [38]. Surprisingly, the least thermodynamically stable atropisomer syn-syn-3 was isolated as a main product and the proportion of isomers 1:2:3 was ca. 8:42:50. This observation stimulated us to further investigate the mechanism of the palladium cross-coupling

• . The atropisomer (syn)-10 of compound (anti)-9 was not detected in the reaction mixture but was obtained through atropisomerisation of (anti)-9 in xylene at 140 °C by prolonged heating (8 h). Compounds 9 and 10 have very similar chromatographic properties and their separation was possible by column

Total synthesis of elansolids B1 and B2

• Liang-Liang Wang and
• Andreas Kirschning

Beilstein J. Org. Chem. 2017, 13, 1280–1287, doi:10.3762/bjoc.13.124

• Flexibacter spec.) (Figure 1) [1][2]. Elansolid A2 (1*), an atropisomer of elansolid A1 (1), showed antibiotic activity against Gram-positive bacteria in the range of 0.2 to 64 µg/mL and cytotoxicity against L929 mouse fibroblast cells with an IC50 value of 12 µg/mL. Besides these two macrocylic members also

Stereodynamic tetrahydrobiisoindole “NU-BIPHEP(O)”s: functionalization, rotational barriers and non-covalent interactions

• Golo Storch,
• Sebastian Pallmann,
• Frank Rominger and
• Oliver Trapp

Beilstein J. Org. Chem. 2016, 12, 1453–1458, doi:10.3762/bjoc.12.141

• preparation of tailor-made functionalized stereodynamic ligands possible and give an outline for possible applications in enantioselective catalysis. Keywords: atropisomer; enantioselective DHPLC; ligand design; non-covalent interactions; Okamoto phases; phosphine ligand; stereodynamic ligands; Introduction

Chemistry of polyhalogenated nitrobutadienes, 14: Efficient synthesis of functionalized (Z)-2-allylidenethiazolidin-4-ones

• Viktor A. Zapol’skii,
• Jan C. Namyslo,
• Mimoza Gjikaj and
• Dieter E. Kaufmann

Beilstein J. Org. Chem. 2014, 10, 1638–1644, doi:10.3762/bjoc.10.170

• Supporting Information File 1). For comparison, the well-known atropisomer 1,1’-binaphthalene-2,2’-diol (BINOL) shows a rotational barrier of 158 kJ/mol with calculated data in good accordance with the experimental value [46]. In addition to substantial NMR, IR, and mass spectral characterization of the

The interplay of configuration and conformation in helical perylenequinones: Insights from chirality induction in liquid crystals and calculations

• Elisa Frezza,
• Silvia Pieraccini,
• Stefania Mazzini,
• Alberta Ferrarini and
• Gian Piero Spada

Beilstein J. Org. Chem. 2012, 8, 155–163, doi:10.3762/bjoc.8.16

• atropisomerization. As a consequence of this process, the sample would contain both cercosporin and its atropisomer. Whereas the former induces a left-handed twist of the nematic director, the latter, having P axial chirality, is expected to induce a twist in the opposite sense, with the net effect of lowering the

Carbamate-directed benzylic lithiation for the diastereo- and enantioselective synthesis of diaryl ether atropisomers

• Abigail Page and
• Jonathan Clayden

Beilstein J. Org. Chem. 2011, 7, 1327–1333, doi:10.3762/bjoc.7.156

• for the synthesis of “nonstandard” atropisomer structures containing rigid fragments joined by a hindered single bond, but which are different from the typically well-studied biaryl compounds [4][5]. These non-biaryl atropisomers have included aromatic amides [6][7][8], ureas [9], ethers [10][11][12

Asymmetric synthesis of biaryl atropisomers by dynamic resolution on condensation of biaryl aldehydes with (−)-ephedrine or a proline- derived diamine

• Ann Bracegirdle,
• Jonathan Clayden and
• Lai Wah Lai

Beilstein J. Org. Chem. 2008, 4, No. 47, doi:10.3762/bjoc.4.47

• % yield. Hydrolysis and reduction of the major diastereoisomeric product of the reaction yields atropisomeric biaryls in >99:1 enantiomeric ratios. Keywords: atropisomer; biaryl; dynamic resolution; ephedrine; imdazolidine; oxazolidine; Introduction Atropisomeric biaryl compounds have proved to be among