Genome mining of labdane-related diterpenoids: Discovery of the two-enzyme pathway leading to (−)-sandaracopimaradiene in the fungus Arthrinium sacchari

• Fumito Sato,
• Terutaka Sonohara,
• Shunta Fujiki,
• Akihiro Sugawara,
• Yohei Morishita,
• Taro Ozaki and
• Teigo Asai

Beilstein J. Org. Chem. 2024, 20, 714–720, doi:10.3762/bjoc.20.65

• GGPP, followed by hydrolysis by acid phosphatase. GC–MS analysis revealed that AsCPS synthesizes the same product to ObCPS_11g (see Supporting Information File 1, Figure S4A and B). It should be noted that the stereochemistry of CPP needs further verification due to the lack of chiral resolution of our

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• octagon-containing carbo[5]helicene was isolated in a 61% yield, which can be further transformed into other chiral hydrocarbon analogues 12 and 13 [35]. Chiral resolution of these helicenes was accomplished by chiral high-performance liquid chromatography (HPLC) and the isomerization barriers were

• , which formed intermediate 109 in a high yield. Finally, DDQ and TfOH induced the Scholl oxidation of 109 to generate 110 in a yield of 24%. Single-crystal X-ray diffraction unambiguously confirmed the helical conformation and a pair of enantiomers. Chiral resolution of enantiomers was achieved by chiral

Menthyl esterification allows chiral resolution for the synthesis of artificial glutamate analogs

• Kenji Morokuma,
• Shuntaro Tsukamoto,
• Kyosuke Mori,
• Kei Miyako,
• Ryuichi Sakai,
• Raku Irie and
• Masato Oikawa

Beilstein J. Org. Chem. 2021, 17, 540–550, doi:10.3762/bjoc.17.48

• enantiospecific synthesis of two artificial glutamate analogs designed based on IKM-159, an antagonist selective to the AMPA-type ionotropic glutamate receptor. The synthesis features the chiral resolution of the carboxylic acid intermediate by the esterification with ʟ-menthol, followed by a configurational

• the activity is controlled by the ring C. Keywords: chiral resolution; configurational analysis; glutamate; metathesis; neuroactivity; Introduction The ionotropic glutamate receptor (iGluR) mediates the majority of the excitatory neurotransmission in the mammalian central nervous system (CNS) and

• the antipode 1*) in 2013 [3]. The synthesis reported herein is based on the menthol-mediated chiral resolution, which was developed de novo thereafter for the enantiospecific synthesis of the seven-membered-ring analogs TKM-107 (2 and the antipode 2*, see Figure 1) and IKM-154 (5 and the antipode 5

Circularly polarized luminescent systems fabricated by Tröger's base derivatives through two different strategies

• Cheng Qian,
• Yuan Chen,
• Qian Zhao,
• Ming Cheng,
• Chen Lin,
• Juli Jiang and
• Leyong Wang

Beilstein J. Org. Chem. 2021, 17, 52–57, doi:10.3762/bjoc.17.6

• -gel was about three times higher than the glum values of R2N-TBPP and S2N-TBPP enantiomers. Interestingly, the CPL handedness of the rac-TBPP/DGG co-gel could be adjusted effectively by changing their stoichiometric ratios. Keywords: circularly polarized luminescence; chiral resolution; co-gelation

Synthetic terpenoids in the world of fragrances: Iso E Super^® is the showcase

• Alexey Stepanyuk and
• Andreas Kirschning

Beilstein J. Org. Chem. 2019, 15, 2590–2602, doi:10.3762/bjoc.15.252

• , (+)-α-bulnesene, (−)-α-guajene, (−)-β-patchoulene and (−)-seychellene) with a slightly camphoraceous, woody balsamic odour [6]. Enzymatic derivatisation of terpenes by means of biocatalysis is another opportunity to create new fragrance molecules or to achieve chiral resolution of racemates. The former

Efficient resolution of racemic crown-shaped cyclotriveratrylene derivatives and isolation and characterization of the intermediate saddle isomer

• Sven Götz,
• Andreas Schneider and
• Arne Lützen

Beilstein J. Org. Chem. 2019, 15, 1339–1346, doi:10.3762/bjoc.15.133

• these studies an intermediate saddle conformer could also be isolated and characterized by 1H and 13C NMR spectroscopy. The HPLC separation method was further developed in order to allow investigations on the racemization behavior of the cyclotriveratrylene derivative. Keywords: chiral resolution

• the intermediate saddle conformer. Results and Discussion Synthesis and chiral resolution of 1 and isolation of the saddle isomer The synthesis of (rac)-1 was accomplished according to the already mentioned protocol by Rousseau and co-workers (Scheme 3) [60] although it should be noted here that

• racemization. This is why Collet and co-workers also developed alternative methods for the chiral resolution of other CTVs and cryptophanes via high-performance liquid chromatography (HPLC) on a CHIRALPAK OT(+) column as stationary phase already in the 1980s [70]. Later on other chiral CTVs could also be

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

• ). For this reason, another strategy of obtaining high % ee of d was employed. Chiral resolution of racemic-d with (R)-menthyl chloroformate gave a high % ee of this key intermediate d. After column chromatographic purification of the crude reaction mixture, the corresponding diastereomers (R)-e or (S)-e

• with TBAF. This racemate then underwent chiral resolution by reacting with (1S)-(−)-camphanic chloride to give a diastereomeric mixture of (R)-h or (S)-h. After separating these diastereomers by column chromatography, the absolute configuration of (S)-h was checked with its X-ray crystal structure

• oxazaborate catalyst for 3, chiral resolution with (R)-menthyl chloroformate for 4 and chiral resolution with (1S)-camphanic chloride for 6. Crystal structures revealed that the presence and absence of additional CF3 substituents in 3 and 6 led to very different structures, as 3 forms helical supramolecular

Molecular recognition of N-acetyltryptophan enantiomers by β-cyclodextrin

• Spyros D. Chatziefthimiou,
• Mario Inclán,
• Petros Giastas,
• Athanasios Papakyriakou,
• Konstantina Yannakopoulou and
• Irene M. Mavridis

Beilstein J. Org. Chem. 2017, 13, 1572–1582, doi:10.3762/bjoc.13.157

• fenoprofen [7], a partial chiral resolution of the racemic mixture occurs, since the obtained crystals contain discrete β-CD dimers enclosing (R)- or (S)-enantiomers in a S/R ratio = 3:1. The enantiomers adopt different orientations in the β-CD dimers and preference of the (S) complex is dictated both by

A new and expeditious synthesis of all enantiomerically pure stereoisomers of rosaprostol, an antiulcer drug

• Wiesława Perlikowska,
• Remigiusz Żurawiński and
• Marian Mikołajczyk

Beilstein J. Org. Chem. 2016, 12, 2234–2239, doi:10.3762/bjoc.12.215

• to 64%. The remaining two stereoisomers, (−)-1b and (+)-1d, were obtained from (−)-1a and (+)-1c in 71 and 68% yield, respectively, by a two-reaction sequence, in which a Mitsunobu inversion of configuration at C-5 was the key step. Keywords: antiulcer drug; chiral resolution; rosaprostol

Chiral gold(I) vs chiral silver complexes as catalysts for the enantioselective synthesis of the second generation GSK-hepatitis C virus inhibitor

• María Martín-Rodríguez,
• Carmen Nájera,
• José M. Sansano,
• Abel de Cózar and
• Fernando P. Cossío

Beilstein J. Org. Chem. 2011, 7, 988–996, doi:10.3762/bjoc.7.111

• %) together with silver acetate (3 mol %), and this afforded moderate enantioselectivities (70–74%) of 5b, in such a way that a further 1,1’-binaphthyl-2,2’-dihydrogen phosphate assisted chiral resolution was required to increase the optical purity of the target molecule [11]. Chiral calcium(II) complexes

Chiral gels derived from secondary ammonium salts of (1R,3S)-(+)-camphoric acid

• Tapas Kumar Adalder,
• N. N. Adarsh,
• Ravish Sankolli and
• Parthasarathi Dastidar

Beilstein J. Org. Chem. 2010, 6, 848–858, doi:10.3762/bjoc.6.100

• . Supramolecular chirality is an important aspect in the development of chiral catalysts [26], chiro-optical switches [44], helical crystallization of proteins and inorganic replicas [45], chiral resolution [46] etc. For this purpose, we have reacted a dibasic acid such as (1R,3S)-(+)-camphoric acid with various