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

• ; stereoselective synthesis; synthetic design; Introduction Rosaprostol (1) is a trade name for 7-(2-hexyl-5-hydroxycyclopentane)heptanoic acid (Figure 1) which belongs to a series of 19,20-dinorprostanoic acid derivatives. It exhibits gastric antisecretory activity and cytoprotective action without the undesired

• stereoselective synthesis of rosaprostols 1a–d. The resolution of (±)-3 and some experimental details are depicted in Scheme 3. It shows also the absolute configurations of (+)-3 and (−)-3 ascribed to the compounds based on their successful conversion into the known rosaprostols 1a and 1c, respectively. Having

Stereoselective synthesis of fused tetrahydroquinazolines through one-pot double [3 + 2] dipolar cycloadditions followed by [5 + 1] annulation

• Xiaofeng Zhang,
• Kenny Pham,
• Shuai Liu,
• Marc Legris,
• Alex Muthengi,
• Jerry P. Jasinski and
• Wei Zhang

Beilstein J. Org. Chem. 2016, 12, 2204–2210, doi:10.3762/bjoc.12.211

• formaldehyde through [5 + 1] annulation to afford a novel polycyclic scaffold bearing tetrahydroquinazoline, pyrrolidine, pyrrolidinedione, and N-substituted maleimide in stereoselective fashion. Keywords: [5 + 1] annulation; [3 + 2] cycloaddition; one-pot reactions; stereoselective synthesis

The direct oxidative diene cyclization and related reactions in natural product synthesis

• Juliane Adrian,
• Leona J. Gross and
• Christian B. W. Stark

Beilstein J. Org. Chem. 2016, 12, 2104–2123, doi:10.3762/bjoc.12.200

• of this polyketide. At this point it has to be mentioned that in 1987 the group of Weiler also used such a permanganate-promoted oxidative cyclization for the stereoselective synthesis of the THF unit in ionomycin [63]. Similarly, in 1980 Walba et al. reported on the B/C-ring fragment synthesis of

• ) was found to be more potent than rollidecin D (70) with selectivity toward the colon cell line HT-29 [108]. In 2001, the groups of Sinha and Keinan reported on a stereoselective synthesis of rollidecin C (69) and D (70) [109] using the tandem oxidative polycyclization reaction with trifluoro

• ], another triterpene natural product found in Jamaican endemic plant Spathelia glabrescens (Rutaceae) [141]. In 1999, Morimoto and co-workers reported on a stereoselective synthesis of the meso-tris-THF natural product teurilene (82) [142][143] (several previous total syntheses existed [144][145][146][147

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

• Lucie Brulíková,
• Aidan Harrison,
• Marvin J. Miller and
• Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

• used by Orena in reactions with cyclopentadiene and cyclohexadiene, giving the products with de values of 74 and 86%, respectively [118]. A series of chiral auxiliaries based on mandelic acid showed similar stereoselectivity benefits and have been proposed by Procter for stereoselective synthesis [109

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• stereoselective synthesis of 1,2-dihydroquinolin-2-ylphosphonates 271 and 1,2-dihydroisoquinolin-1-ylphosphonates 272 via the three-component reactions of quinoline or isoquinoline, dialkyl acetylenedicarboxylates 269, and dialkyl phosphonates 270 has been described by Shaabani et al. (Scheme 56) [94]. The

• -(aminothioxomethyl)-1,2-dihydroisoquinolin-1-yl]phosphonates. Three-component stereoselective synthesis of 1,2-dihydroquinolin-2-ylphosphonates and 1,2-dihydroisoquinolin-1-ylphosphonates. Diphosphorylation of diazaheterocyclic compounds via a tandem 1,4–1,2 addition of dimethyl trimethylsilyl phosphite

• proline with aldehydes and dialkyl phosphites for the synthesis of pyrrolidinylphosphonates. Three-component domino aza-Wittig/phospha-Mannich sequence for the phosphorylation of isatin derivatives. Stereoselective synthesis of phosphorylated trans-1,5-benzodiazepines via a one-pot three-component

Stereoselective synthesis of tricyclic compounds by intramolecular palladium-catalyzed addition of aryl iodides to carbonyl groups

• Jakub Saadi,
• Christoph Bentz,
• Kai Redies,
• Dieter Lentz,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1236–1242, doi:10.3762/bjoc.12.118

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• researchers have developed methods for the stereoselective synthesis of tertiary carbon stereocenters. One aesthetically pleasing approach is the enantioselective protonation of prochiral enolates and enolate equivalents [1][2][3][4][5][6][7][8][9][10]. While an attractive strategy, the enantioselective

Modular synthesis of the pyrimidine core of the manzacidins by divergent Tsuji–Trost coupling

• Sebastian Bretzke,
• Stephan Scheeff,
• Felicitas Vollmeyer,
• Friederike Eberhagen,
• Frank Rominger and
• Dirk Menche

Beilstein J. Org. Chem. 2016, 12, 1111–1121, doi:10.3762/bjoc.12.107

• . Application of the concept for manzacidin core synthesis After proofing the general adaptability of our synthetic concept, we next evaluated the applicability of this procedure for the synthesis of the authentic manzacidin substrate. As shown in Scheme 5, we first focused on the stereoselective synthesis of

• urea-type cyclization precursor 19. Stereodivergent synthesis of 1,3-syn- and anti-tetrahydropyrimidinones [31]. Stereoselective synthesis of all possible stereoisomers of the manzacidin core amine by asymmetric addition to chiral tert-butanesulfinyl ketimines. Synthesis of the authentic cyclization

Towards the total synthesis of keramaphidin B

• Pavol Jakubec,
• Alistair J. M. Farley and
• Darren J. Dixon

Beilstein J. Org. Chem. 2016, 12, 1096–1100, doi:10.3762/bjoc.12.104

• wish to report our preliminary synthetic efforts towards the stereoselective synthesis of the heavily functionalised piperidine core of keramaphidin B (1). Results and Discussion Our overall synthetic strategy is presented in Figure 2. We envisaged that a late stage alkyne RCM reaction of 2 and cis

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

A convenient route to symmetrically and unsymmetrically substituted 3,5-diaryl-2,4,6-trimethylpyridines via Suzuki–Miyaura cross-coupling reaction

• Dariusz Błachut,
• Joanna Szawkało and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2016, 12, 835–845, doi:10.3762/bjoc.12.82

• approach in the determination of the enantiomeric purity of (+)-crispine [81] and (R)-(+)-harmicine after their stereoselective synthesis [82]. The results of a more detailed study on the stereochemistry of atropisomeric enantiomers will be published elsewhere. Conclusion Herein, we described an easy and

Opportunities and challenges for direct C–H functionalization of piperazines

• Zhishi Ye,
• Kristen E. Gettys and
• Mingji Dai

Beilstein J. Org. Chem. 2016, 12, 702–715, doi:10.3762/bjoc.12.70

• the diamine switch strategy and α-methylbenzyl chiral auxiliary strategy has been reported to give the best results and produce 51 in 70% yield and 90:10 diastereoselectivity (Figure 11, reaction 3). O’Brien and co-workers also reported a stereoselective synthesis of enantiopure 2,6-trans- and 2,5

Mycothiol synthesis by an anomerization reaction through endocyclic cleavage

• Shino Manabe and
• Yukishige Ito

Beilstein J. Org. Chem. 2016, 12, 328–333, doi:10.3762/bjoc.12.35

• . Results and Discussion Based on the results of our previous study, we expected that an anomerization would be useful for the stereoselective synthesis of α-aminoglycosides, which is normally difficult by conventional glycosylation reactions. β-Glycoside 2, which is synthesized by assistance from the

Asymmetric α-amination of β-keto esters using a guanidine–bisurea bifunctional organocatalyst

• Minami Odagi,
• Yoshiharu Yamamoto and
• Kazuo Nagasawa

Beilstein J. Org. Chem. 2016, 12, 198–203, doi:10.3762/bjoc.12.22

• important synthetic route to optically active α-amino acid derivatives with chiral quaternary stereocenters [1][2]. Since an α-amino acid moiety is frequently found in biologically active compounds, considerable efforts have been made to achieve a stereoselective synthesis of this structure [3][4]. In

A novel and practical asymmetric synthesis of dapoxetine hydrochloride

• Yijun Zhu,
• Zhenren Liu,
• Hongyan Li,
• Deyong Ye and
• Weicheng Zhou

Beilstein J. Org. Chem. 2015, 11, 2641–2645, doi:10.3762/bjoc.11.283

• . The optical rotation value of compound 1 was consistent with that previously reported [15], which confirmed that the S-enantiomer of dapoxetine hydrochloride was synthesized successfully by using this route. Conclusion In summary, a novel and stereoselective synthesis of dapoxetine hydrochloride

Stereoselective synthesis of hernandulcin, peroxylippidulcine A, lippidulcines A, B and C and taste evaluation

• Marco G. Rigamonti and
• Francesco G. Gatti

Beilstein J. Org. Chem. 2015, 11, 2117–2124, doi:10.3762/bjoc.11.228

• Marco G. Rigamonti Francesco G. Gatti Chemistry Department “G. Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 1, 20133 Milano, Italy 10.3762/bjoc.11.228 Abstract The first stereoselective synthesis of lippidulcines A, B and C has been accomplished starting from (+)-hernandulcin, which

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• this method by isolating the RCM product of the ROM–CM byproduct 290, which was recovered in the ROM–RCM–CM cascade (Scheme 62). Kouklovsky and co-workers [62] have described a stereoselective synthesis of 2-(2-hydroxyalkyl)piperidine alkaloids by employing a RRM of NDA adduct 293. The required

Synthesis of 1,2-cis-2-C-branched aryl-C-glucosides via desulfurization of carbohydrate based hemithioacetals

• Henok H. Kinfe,
• Fanuel M. Mebrahtu,
• Mandlenkosi M. Manana,
• Kagiso Madumo and
• Mokela S. Sokamisa

Beilstein J. Org. Chem. 2015, 11, 583–588, doi:10.3762/bjoc.11.64

• -branched C-, S-, and N-glycosides is less explored [11]. Herein, we wish to report a stereoselective strategy for the synthesis of 1,2-cis-2-C-branched aryl-C-glucosides. Results and Discussion We recently reported on the stereoselective synthesis of carbohydrate based thiochroman 1 whereby the C-1 and C-2

• conclusion, we have demonstrated that desulfurization of carbohydrate based hemithioacetals 3 allows for the stereoselective synthesis of 2-C-branched 1,2-cis-aryl-C-glucosides. The method has been applied to the synthesis of either 1,2-cis-2-hydroxymethyl or 2-carbaldehyde of aryl-C-glucosides from a common

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