Stereoselective cathodic synthesis of 8-substituted (1R,3R,4S)-menthylamines

• Carolin Edinger,
• Jörn Kulisch and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2015, 11, 294–301, doi:10.3762/bjoc.11.34

• , if the size of the substituent is further increased, the electrochemical conversion is significantly impaired. Structural features of 8-substituted menthylamines 1. Synthetic strategies to menthylamines. Stereoselective synthesis of 8-substituted (1R,3R,4S)-menthylamines. Influence of the cathode

NAA-modified DNA oligonucleotides with zwitterionic backbones: stereoselective synthesis of A–T phosphoramidite building blocks

• Boris Schmidtgall,
• Claudia Höbartner and
• Christian Ducho

Beilstein J. Org. Chem. 2015, 11, 50–60, doi:10.3762/bjoc.11.8

• of the NAA-linkage at T–T sites, it is now envisioned to prepare NAA-modified oligonucleotides bearing the modification at X–T motifs (X = A, C, G). We have therefore developed the efficient and stereoselective synthesis of NAA-linked 'dimeric' A–T phosphoramidite building blocks for automated DNA

• to further establish the NAA-linkage as a useful addition to the existing 'toolbox' of backbone modifications for the design of bioactive oligonucleotide analogues. Keywords: backbone modifications; DNA; nucleic acids; oligonucleotides; stereoselective synthesis; zwitterions; Introduction

• oligonucleotide sequence with a T in 3'-direction, thus significantly broadening the applicability of the modification. In this work, we describe the stereoselective synthesis of 'dimeric' NAA-linked A–T phosphoramidites (S)-7 and (R)-7 (Figure 1) as well as their application in automated DNA synthesis. This

Stereoselective synthesis of perillaldehyde-based chiral β-amino acid derivatives through conjugate addition of lithium amides

• Zsolt Szakonyi,
• Reijo Sillanpää and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2014, 10, 2738–2742, doi:10.3762/bjoc.10.289

A general metal-free approach for the stereoselective synthesis of C-glycals from unactivated alkynes

• Shekaraiah Devari,
• Manjeet Kumar,
• Ramesh Deshidi,
• Masood Rizvi and
• Bhahwal Ali Shah

Beilstein J. Org. Chem. 2014, 10, 2649–2653, doi:10.3762/bjoc.10.277

• biologically active natural products, such as palytoxin, spongistatin, vitexin, orientin, bergenin and halichondrin [1][2][3][4][5]. Over the years myriad methods have appeared for their efficient and stereoselective synthesis [6][7][8][9][10][11][12]. Among these methods, C-alkynylation [13][14][15][16] is of

Regio- and stereoselective synthesis of new diaminocyclopentanols

• Evgeni A. Larin,
• Valeri S. Kochubei and
• Yuri M. Atroshchenko

Beilstein J. Org. Chem. 2014, 10, 2513–2520, doi:10.3762/bjoc.10.262

• epoxide carbons can react with a nucleophile to produce regioisomeric aminocyclitols. Herein, we describe the regio- and stereoselective synthesis of diaminocyclopentanol derivatives from N-protected cyclopentanamine epoxides using nitrogen-containing nucleophiles. Results and Discussion Preparation of

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

• methodologies utilizing phosphonamides will be discussed, followed by an overview of synthetic routes for the preparation of phosphonamide reagents. Review Phosphonamides in stereoselective synthesis For the purpose of this review, only phosphonamide methodologies with applications in the synthesis of natural

• reactions are those derived from 1-(tert-butylamino)-2-methylpropan-2-ol. Denmark and Amburgey used this type of phosphonamides in a four-step protocol for the highly stereoselective synthesis of trisubstituted alkenes [21]. The application of cyclic phosphonamides was further extended toward asymmetric

• an unsymmetrical phosphonamide of type 64 was used in the synthesis of PTP inhibitors [68], and methyl jasmonate [48], as discussed later in this review. Nucleophilic displacement The stereoselective synthesis of unsymmetrical phosphonamides 67 by nucleophilic displacement was reported by Hua and co

One-pot stereoselective synthesis of α,β-differentiated diamino esters via the sequence of aminochlorination, aziridination and intermolecular S_N2 reaction

• Yiwen Xiong,
• Ping Qian,
• Chenhui Cao,
• Haibo Mei,
• Jianlin Han,
• Guigen Li and
• Yi Pan

Beilstein J. Org. Chem. 2014, 10, 1802–1807, doi:10.3762/bjoc.10.189

Stereoselective synthesis of carbocyclic analogues of the nucleoside Q precursor (PreQ₀)

• Sabin Llona-Minguez and
• Simon P. Mackay

Beilstein J. Org. Chem. 2014, 10, 1333–1338, doi:10.3762/bjoc.10.135

• & Biophysics, Karolinska Institutet, Stockholm, S-171 21, Sweden 10.3762/bjoc.10.135 Abstract A convergent and stereoselective synthesis of chiral cyclopentyl- and cyclohexylamine derivatives of nucleoside Q precursor (PreQ0) has been accomplished. This synthetic route allows for an efficient preparation of 4

• diastereoselectivity [36], but since initially we did not require an enantioselective synthesis and the Zhou method employed rather expensive reagents, we investigated a simpler and cheaper route to access both cis- and trans-isomers. We envisioned a stereoselective synthesis that would potentially allow for the

• reacted with chloro-intermediate 9 and the pivalamide groups were cleaved under basic hydrolysis conditions to yield 21 and 22. Conclusion In conclusion, a concise and stereoselective synthesis of novel cyclopentyl and cyclohexyl analogues of PreQ0 has been developed to expand our fragment-based kinase

Synthesis of chiral N-phosphoryl aziridines through enantioselective aziridination of alkenes with phosphoryl azide via Co(II)-based metalloradical catalysis

• Jingran Tao,
• Li-Mei Jin and
• X. Peter Zhang

Beilstein J. Org. Chem. 2014, 10, 1282–1289, doi:10.3762/bjoc.10.129

• resultant enantioenriched N-phosphorylaziridines may find potential applications in stereoselective synthesis of both nitrogen- and phosphorous-containing compounds. Efforts are underway to employ phosphoryl azides as effective nitrene sources for other types of organic transformations via Co(II)-based

Synthesis of a sucrose dimer with enone tether; a study on its functionalization

• Zbigniew Pakulski,
• Norbert Gajda,
• Magdalena Jawiczuk,
• Jadwiga Frelek,
• Piotr Cmoch and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2014, 10, 1246–1254, doi:10.3762/bjoc.10.124

• oxidized with osmium tetroxide to a diol. Absolute configurations of the allylic alcohol as well as the diol were determined by circular dichroism (CD) spectroscopy using the in situ dimolybdenum methodology. Keywords: CD-spectroscopy; Cotton effect; multivalent glycosystems; osmylation; stereoselective

• synthesis; sucrose; Introduction Molecular recognition is one of the most important phenomena in stereoselective processes. Chiral crown ethers (or analogs) are particularly useful in enantioselective reactions [1][2] as well as differentiation of chiral guests [3][4]. From all of the chiral platforms

Amino acid motifs in natural products: synthesis of O-acylated derivatives of (2S,3S)-3-hydroxyleucine

• Oliver Ries,
• Martin Büschleb,
• Markus Granitzka,
• Dietmar Stalke and
• Christian Ducho

Beilstein J. Org. Chem. 2014, 10, 1135–1142, doi:10.3762/bjoc.10.113

• moiety to the muraymycin scaffold. As part of our synthetic studies on muraymycins and their analogues [19][20][21][22][23][24], including investigations on the unusual ω-functionalized fatty acid motif found in muraymycin A1 (1a) [25], we identified the need for a highly stereoselective synthesis of (2S

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• stereoselective synthesis of chiral chlorophosphine boranes 11a [39]. The borane complex has a good configurational stability with borane as a protecting group, in contrast to chlorophosphines that can undergo inversion at the phosphorus center [30]. They allow the synthesis of a variety of P-chiral tertiary

Regioselective S_N2' Mitsunobu reaction of Morita–Baylis–Hillman alcohols: A facile and stereoselective synthesis of α-alkylidene-β-hydrazino acid derivatives

• Silong Xu,
• Jian Shang,
• Junjie Zhang and
• Yuhai Tang

Beilstein J. Org. Chem. 2014, 10, 990–995, doi:10.3762/bjoc.10.98

Asymmetric total synthesis of a putative sex pheromone component from the parasitoid wasp Trichogramma turkestanica

• Danny Geerdink,
• Jeffrey Buter,
• Teris A. van Beek and
• Adriaan J. Minnaard

Beilstein J. Org. Chem. 2014, 10, 761–766, doi:10.3762/bjoc.10.71

• -dien-1-ol (2, Figure 1) [6]. The absolute configurations of the putative pheromone components, however, remained unknown. To solve this problem we undertook the stereoselective synthesis of 2, thereby arbitrarily choosing the all-S configuration. Results and Discussion Nowadays, a number of efficient

Synthesis of (2S,3R)-3-amino-2-hydroxydecanoic acid and its enantiomer: a non-proteinogenic amino acid segment of the linear pentapeptide microginin

• Rajendra S. Rohokale and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2014, 10, 667–671, doi:10.3762/bjoc.10.59

• anticancer drug taxol [9]. Due to the biological importance of (2S,3R)-AHDA, the enantioselective synthesis of its chiral core is a challenge task. This fact led to several approaches for the stereoselective synthesis of (2S,3R)-AHDA including (i) the enantioselective introduction of amino- and hydroxy

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

• Peter H. Huy,
• Julia C. Westphal and
• Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

Efficient carbon-Ferrier rearrangement on glycals mediated by ceric ammonium nitrate: Application to the synthesis of 2-deoxy-2-amino-C-glycoside

• Alafia A. Ansari,
• Y. Suman Reddy and
• Yashwant D. Vankar

Beilstein J. Org. Chem. 2014, 10, 300–306, doi:10.3762/bjoc.10.27

• rearrangement of glycals by using ceric ammonium nitrate and several carbon nucleophiles. We have successfully employed the obtained C-allyl glycoside 2a for the stereoselective synthesis of a orthogonally protected 2-deoxy-2-amino-C-glycoside 12 via an Overman rearrangement as a key step. nOe and decoupling

Flow microreactor synthesis in organo-fluorine chemistry

• Hideki Amii,
• Aiichiro Nagaki and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2013, 9, 2793–2802, doi:10.3762/bjoc.9.314

• microreactor provided improved reaction control over traditional batch reactors; high-yield synthesis of fluorinated epoxides was achieved (Scheme 3). Kitazume et al. demonstrated the benefit of flow microreactors for a highly stereoselective synthesis of difluoromethylated alkenes [51]. They succeeded in

Garner’s aldehyde as a versatile intermediate in the synthesis of enantiopure natural products

• Mikko Passiniemi and
• Ari M.P. Koskinen

Beilstein J. Org. Chem. 2013, 9, 2641–2659, doi:10.3762/bjoc.9.300

• )-vinyl nucleophiles created from the vinyl iodide 61 in the stereoselective synthesis of pachastrissamine (11) [81][82] and norfuranomycin [37] (Scheme 23). After halogen–metal exchange with n-BuLi, the newly formed nucleophile reacts with (S)-1. When HMPT or dimethylpropyleneurea (DMPU) were used, high

Synthesis of enantiomerically pure (2S,3S)-5,5,5-trifluoroisoleucine and (2R,3S)-5,5,5-trifluoro-allo-isoleucine

• Holger Erdbrink,
• Elisabeth K. Nyakatura,
• Susanne Huhmann,
• Ulla I. M. Gerling,
• Dieter Lentz,
• Beate Koksch and
• Constantin Czekelius

Beilstein J. Org. Chem. 2013, 9, 2009–2014, doi:10.3762/bjoc.9.236

• Holger Erdbrink Elisabeth K. Nyakatura Susanne Huhmann Ulla I. M. Gerling Dieter Lentz Beate Koksch Constantin Czekelius Department of Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany 10.3762/bjoc.9.236 Abstract A practical route for the stereoselective

• synthesis of (2S,3S)-5,5,5-trifluoroisoleucine (L-5-F3Ile) and (2R,3S)-5,5,5-trifluoro-allo-isoleucine (D-5-F3-allo-Ile) was developed. The hydrophobicity of L-5-F3Ile was examined and it was incorporated into a model peptide via solid phase peptide synthesis to determine its α-helix propensity. The α-helix

Stereoselective synthesis of the C79–C97 fragment of symbiodinolide

• Hiroyoshi Takamura,
• Takayuki Fujiwara,
• Isao Kadota and
• Daisuke Uemura

Beilstein J. Org. Chem. 2013, 9, 1931–1935, doi:10.3762/bjoc.9.228

• . Therefore, in order to complete the configurational elucidation of 1, we are now investigating its chemical degradation [1][2][3] and chemical synthesis of the fragments [4][5][6][7][8][9][10][11]. Previously, we reported the stereoselective synthesis of the spiroacetal C79–C96 fragment [4], which is

• Information File 1). In conclusion, we have achieved the stereoselective synthesis of the C79–C97 fragment. The synthetic route has featured a stereoselective spiroacetalization, a Julia–Kocienski olefination, and a Sharpless asymmetric dihydroxylation. This synthesis of the spiroacetal fragment, wherein the

Creating Complexity

• Donald Craig

Beilstein J. Org. Chem. 2013, 9, 1881–1882, doi:10.3762/bjoc.9.220

• of catalysis, radical chemistry, stereoselective synthesis and molecular diversity. I thank them warmly for their high-quality contributions, which demonstrate the central role of organic synthesis in all its guises, in the creation of complexity. Donald Craig London, July 2013

Synthesis of mucin-type O-glycan probes as aminopropyl glycosides

• David Benito-Alifonso,
• Rachel A. Jones,
• Anh-Tuan Tran,
• Hannah Woodward,
• Nichola Smith and
• M. Carmen Galan

Beilstein J. Org. Chem. 2013, 9, 1867–1872, doi:10.3762/bjoc.9.218

• galactosamine derivative 8 as the key intermediate. This was prepared in a three-step, high yielding stereoselective synthesis from commercially available galactosamine hydrochloride in 66% yield as previously reported [16]. From chloride 8, 3-azidopropyl moiety 11 was accessed in a three-step process in 79

Synthesis of the reported structure of piperazirum using a nitro-Mannich reaction as the key stereochemical determining step

• James C. Anderson,
• Andreas S. Kalogirou,
• Michael J. Porter and
• Graham J. Tizzard

Beilstein J. Org. Chem. 2013, 9, 1737–1744, doi:10.3762/bjoc.9.200

• unambiguously assigned by single crystal X-ray diffraction but the spectroscopic data did not match those reported for the natural product. The structure of the natural product must therefore be revised. Keywords: alkaloid; aza-Henry; natural products; nitro-Mannich; piperazinone; stereoselective synthesis