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

• report are highly stereoselective (we hesitate to use the term stereospecific here since the mass balances are often too low to rigorously exclude the formation of other diastereomers) since the configuration of the cyclic precursor ketones 3–5 is transferred to that of the cyclization products as shown

Bifunctional catalysis

• Darren J. Dixon

Beilstein J. Org. Chem. 2016, 12, 1079–1080, doi:10.3762/bjoc.12.102

• product and drug target synthesis. The creativity and productivity of the researchers in the field in general, and the breadth of highly stereoselective reactions reported in this series in particular, is truly impressive, and I would like to express my sincere gratitude to all of the many contributors

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

• contain two biologically important structural scaffolds, namely the 3-hydroxyoxindole and coumarin, which could be potentially used for further biological evaluation or serve as starting points in drug discovery pursuits. A highly stereoselective Mukaiyama–aldol reaction was reported by Zhou and co

• cyclization, giving the tricyclic N-heterocyclic core. Very recently, Shi and co-workers reported the chiral phosphoric acid (CPA, cat. 31)-catalyzed asymmetric dearomatization reactions of tryptamines with 3-indolyl-3-hydroxyoxindoles, affording the indole-containing tricyclic N-heterocycles in a highly

• stereoselective manner (up to 99% yield, >95:5 dr and 95:5 er, Scheme 49) [65]. The electronic properties of the substituents had a remarkable effect on the yields and enantioselectivities. Mechanistically, the CPA dually activated both substrates through hydrogen-bond interactions. Tryptamines acted as

Scope and mechanism of the highly stereoselective metal-mediated domino aldol reactions of enolates with aldehydes

• M. Emin Cinar,
• Bernward Engelen,
• Martin Panthöfer,
• Hans-Jörg Deiseroth,
• Jens Schlirf and
• Michael Schmittel

Beilstein J. Org. Chem. 2016, 12, 813–824, doi:10.3762/bjoc.12.80

• the years [31]. We have already reported a domino aldol–aldol–hemiacetal process that furnishes racemic tetrahydro-2H-pyran-2,4-diols in a highly stereoselective manner (Scheme 1) [30][31][32][33][34][35][36][37]. In this paper, the domino aldol–aldol–hemiacetal reaction involving several metals (Al

Supported bifunctional thioureas as recoverable and reusable catalysts for enantioselective nitro-Michael reactions

• José M. Andrés,
• Miriam Ceballos,
• Alicia Maestro,
• Isabel Sanz and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2016, 12, 628–635, doi:10.3762/bjoc.12.61

• , entries 10 and 12). The improvement of that process is under study. Conclusion In summary, supported bifunctional thioureas on sulfonylpolystyrene are able to promote highly stereoselective nitro-Michael reactions with different nucleophiles. The activity of the catalysts varies with the length of the

Recent advances in N-heterocyclic carbene (NHC)-catalysed benzoin reactions

• Rajeev S. Menon,
• Akkattu T. Biju and
• Vijay Nair

Beilstein J. Org. Chem. 2016, 12, 444–461, doi:10.3762/bjoc.12.47

• . Although the presence of an isoxazole moiety is not a prerequisite for the success of this annulation, its rigid nature presumably renders the reaction highly stereoselective [47]. This simple and mild method allowed the construction of orthogonally protected polycyclic quinones from readily available

Scope and limitations of the dual-gold-catalysed hydrophenoxylation of alkynes

• Adrián Gómez-Suárez,
• Yoshihiro Oonishi,
• Anthony R. Martin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2016, 12, 172–178, doi:10.3762/bjoc.12.19

• [24][25]. This transformation proceeds through the interaction of the gold centres with both the phenol and the alkyne motifs, thus generating a synergistic effect that produces unique catalytic activity (Scheme 1) [24][25]. In addition, this reaction is highly stereoselective and only the Z-isomer

Synthesis of Xenia diterpenoids and related metabolites isolated from marine organisms

• Tatjana Huber,
• Lara Weisheit and
• Thomas Magauer

Beilstein J. Org. Chem. 2015, 11, 2521–2539, doi:10.3762/bjoc.11.273

• 149 in 55% yield. A highly stereoselective Simmons–Smith reaction [70] delivered the cyclopropyl ring exclusively from the accessible α-face to give 150. The synthesis of (+)-acetoxycrenulide (151) was completed in seven further steps and in summary proceeded in 33 steps (longest linear sequence) and

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• and 10 in a highly stereoselective fashion. In view of this findings, it appeared that deterioration of the enantiomeric excess of the both APIs isomers [Δ% ee = 9–15 for (R)-(+)-8 (>99% ee) and Δ% ee = 3–4 for (S)-(−)-8 (96% ee)] synthesized in toluene may be related to the fact that this process

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

• achiral anhydrides followed by Curtius degradation [18][19][20]. The highly stereoselective Michael addition of lithium amide-type nucleophiles to α,β-unsaturated esters also proved to be a very efficient and useful method for the preparation of alicyclic β-amino acids in homochiral form [21][22

• substituent could be investigated. The addition was proven highly stereoselective (de > 99%), based on the 1H NMR data of the crude product and cis-amino ester 11 as a single product was obtained in gram-scale quantities and high yield (Scheme 4). In addition to the NOESY examinations, the relative

• 10D (see Scheme 2). Conclusion In conclusion, the highly stereoselective Michael addition of lithium dibenzylamide and (R)-N-benzyl-N-α-methylbenzylamide to tert-butyl perillate (3) proved to be an efficient method for the preparation of limonene-based β-amino acids through the three-step

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

• challenge. We reasoned that the development of a strategy which in situ activates the terminal alkyne and further catalyzes the reaction without the aid of other Lewis acids might be a solution to this problem. Thus, in continuation of our efforts [36][37][38], we describe a highly stereoselective TMSOTf

Chiral phosphines in nucleophilic organocatalysis

• Yumei Xiao,
• Zhanhu Sun,
• Hongchao Guo and
• Ohyun Kwon

Beilstein J. Org. Chem. 2014, 10, 2089–2121, doi:10.3762/bjoc.10.218

• carbonate and the carboxylic ester of methyleneindolinone shielding one possible attacking face during the nucleophilic attack (Scheme 38). In 2013, using the same catalytic system, Barbas and co-workers further developed highly stereoselective phosphine-catalyzed [3 + 2] annulations of MBH carbonates with

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

• 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

Design and synthesis of multivalent neoglycoconjugates by click conjugations

• Feiqing Ding,
• Li Ji,
• Ronny William,
• Hua Chai and
• Xue-Wei Liu

Beilstein J. Org. Chem. 2014, 10, 1325–1332, doi:10.3762/bjoc.10.134

• Feiqing Ding Li Ji Ronny William Hua Chai Xue-Wei Liu Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371 10.3762/bjoc.10.134 Abstract A highly stereoselective BF3∙OEt2-promoted tandem

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

One-pot three-component synthesis and photophysical characteristics of novel triene merocyanines

• Christian Muschelknautz,
• Robin Visse,
• Jan Nordmann and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 599–612, doi:10.3762/bjoc.10.51

• spectrometry and by combustion analysis. The appearance of only a single set of signals in the NMR spectra indicates that the process is highly stereoselective. The occurrence of deep-colored products indicates the presence of a chromophore with extended π-electron conjugation where the terminal acceptor and

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

Synthesis of new enantiopure poly(hydroxy)aminooxepanes as building blocks for multivalent carbohydrate mimetics

• Léa Bouché,
• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 213–223, doi:10.3762/bjoc.10.17

• enantiopure nitrones and lithiated TMSE-allene we prepared three 1,2-oxazine derivatives which underwent a highly stereoselective Lewis acid-induced rearrangement to give bicyclic products in good yield. Subsequent reductive transformations delivered a library of new poly(hydroxy)aminooxepane derivatives. The

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

Bidirectional cross metathesis and ring-closing metathesis/ring opening of a C₂-symmetric building block: a strategy for the synthesis of decanolide natural products

• Bernd Schmidt and
• Oliver Kunz

Beilstein J. Org. Chem. 2013, 9, 2544–2555, doi:10.3762/bjoc.9.289

• one step. An example recently published by us combines RCM of butenoates 2 with a base-induced highly stereoselective ring opening of the transient metathesis products 4, furnishing exclusively Z,E-dienes 3 [24]. We assume that the reaction proceeds via formation of an enolate 5, followed by

Total synthesis of (−)-epimyrtine by a gold-catalyzed hydroamination approach

• Thi Thanh Huyen Trinh,
• Khanh Hung Nguyen,
• Patricia de Aguiar Amaral and
• Nicolas Gouault

Beilstein J. Org. Chem. 2013, 9, 2042–2047, doi:10.3762/bjoc.9.242

• of (−)-epimyrtine have been described to date including the intramolecular allylsilane N-acyliminium ion cyclization [6], the organocatalytic aza-Michael reaction [7], the intramolecular Mannich reaction [8], and the iminium ion cascade reaction [9][10]. More efficient, convenient and highly

• stereoselective synthetic routes are still being sought after. In the past decades, gold catalysis has emerged as an important tool in a plethora of fields of synthetic organic chemistry, and after methodological investigations [11][12][13][14][15][16], the good functional group compatibility of gold catalysts

A reductive coupling strategy towards ripostatin A

• Kristin D. Schleicher and
• Timothy F. Jamison

Beilstein J. Org. Chem. 2013, 9, 1533–1550, doi:10.3762/bjoc.9.175

• synthesis [66]. The lithiated cyanohydrin acetonides react as nucleophiles with alkyl, allyl, and propargyl halides, as well as with epoxides. Although the alkylation itself is highly stereoselective in favor of the axial nitrile, the syn-1,3-diol stereochemistry is ultimately set in a subsequent reductive

Preparation of optically active bicyclodihydrosiloles by a radical cascade reaction

• Koichiro Miyazaki,
• Yu Yamane,
• Ryuichiro Yo,
• Hidemitsu Uno and
• Akio Kamimura

Beilstein J. Org. Chem. 2013, 9, 1326–1332, doi:10.3762/bjoc.9.149

• reactions progressed in a highly stereoselective manner. Further application of the present silole synthesis is now underway in our laboratory. Experimental General methods: All 1H and 13C NMR spectra were recorded on a JEOL JNM-ECA500 Delta2 (500 MHz for 1H, 126 MHz for 13C) spectrometer. All the reactions

Exploration of an epoxidation–ring-opening strategy for the synthesis of lyconadin A and discovery of an unexpected Payne rearrangement

• Brad M. Loertscher,
• Yu Zhang and
• Steven L. Castle

Beilstein J. Org. Chem. 2013, 9, 1179–1184, doi:10.3762/bjoc.9.132

• efficiently furnish its bicyclo[5.4.0]undecane system, which is shown in bold in Figure 1. Subsequent to this observation, we performed model studies that demonstrated the viability of highly stereoselective 7-exo-trig acyl radical–6-exo-trig alkyl radical cyclizations as a means of preparing bicyclo[5.4.0

• epoxide 25. A Myers alkylation and a reagent-controlled Shi epoxidation were used to construct this compound in a highly stereoselective fashion. The bulky trityl group of 25 was intended to serve as a means of directing a ring-opening reaction to the distal carbon of the epoxide [19][20][21][22]. However

• Brad M. Loertscher Yu Zhang Steven L. Castle Department of Chemistry and Biochemistry, Brigham Young University, C100 BNSN, Provo, UT, 84602, USA 10.3762/bjoc.9.132 Abstract In the context of synthetic efforts targeting the alkaloid lyconadin A, scalemic epoxide 25 was prepared by a highly

Appel-reagent-mediated transformation of glycosyl hemiacetal derivatives into thioglycosides and glycosyl thiols

• Tamashree Ghosh,
• Abhishek Santra and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2013, 9, 974–982, doi:10.3762/bjoc.9.112

• thiol derivatives by the treatment of glycosyl bromide derivatives with the in situ generated sodium carbonotrithioate (a combination of CS2 and Na2S·9H2O) [43]. Although, the reaction is highly stereoselective and high yielding it involves the handling of unstable glycosyl bromide. Therefore, as an

• carbonotrithioate (derived from the reaction of CS2 and Na2S·9H2O) furnished thioglycosides and glycosyl thiols in excellent yield with high stereoselectivity in a two-step, one-pot reaction condition. The reaction condition is operationally simple, mild, reproducible, high-yielding, highly stereoselective, and can