(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers

• Giorgos Koutoulogenis,
• Nikolaos Kaplaneris and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48

• desired products in excellent yields and selectivities. In order to broaden the utility of this methodology, the authors reduced the nitro group to an amine. The product was in situ transformed to the tricyclic product 102, through a diastereoselective reductive amination, that controlled the

• epimerization to the sole product 193. Their postulation is based on the fact that Henry reactions are typically reversible, so 194 and 195 could be involved in a retro-Henry and subsequent diastereoselective Henry reaction, where the stereochemical outcome is inducted by the C2 stereochemistry. This is further

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

• , diastereoselective reduction of the cross-benzoin products with NaBH4 afforded valuable syn-diol products. Goodman and Johnson disclosed a dynamic kinetic resolution of β-halo-α-ketoesters via NHC-catalysed asymmetric cross-benzoin reaction. Here, the cross-benzoin reaction of aromatic aldehydes with β-stereogenic-α

• ]. Meanwhile, the Breslow intermediate is produced from the aldehyde by the thiazolium 31-derived NHC. The union of these two reactive intermediates furnished α-amidoketones 32 in excellent yields (Scheme 18). A diastereoselective [4 + 1] annulation of phthalaldehyde with imines leading to the formation of cis

• influence of these catalysts on the diastereoselectivity of the reaction was also studied using NMR techniques. An NHC-catalysed intramolecular benzoin condensation of carbohydrate-derived dialdehydes has been applied for the construction of carbocyclic sugars. Diastereoselective benzoin reactions of manno

Cupreines and cupreidines: an established class of bifunctional cinchona organocatalysts

• Laura A. Bryant,
• Rossana Fanelli and
• Alexander J. A. Cobb

Beilstein J. Org. Chem. 2016, 12, 429–443, doi:10.3762/bjoc.12.46

• -bonding moiety of the 6’-OH in the catalyst is essential in directing the reaction towards the anti-diastereoselective pathway. Secondly, the solvent was critical in the diastereocontrol of the reaction. This is put down to the fact that the solvent can have an important influence on the conformation of

Self and directed assembly: people and molecules

• Tony D. James

Beilstein J. Org. Chem. 2016, 12, 391–405, doi:10.3762/bjoc.12.42

• catalyst of diastereoselective aza-Diels–Alder reactions [68] (Figure 14). While, the structure of the “chiral boron reagent” still remains unknown during our investigation of analogues we discovered a very interesting three-component self-assembly. Chiral binol, a chiral amine and 2-formylbenzeneboronic

Diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues

• Charlotte Collet,
• Françoise Chrétien,
• Yves Chapleur and
• Sandrine Lamandé-Langle

Beilstein J. Org. Chem. 2016, 12, 353–361, doi:10.3762/bjoc.12.39

• Charlotte Collet Francoise Chretien Yves Chapleur Sandrine Lamande-Langle Université de Lorraine, Vandoeuvre-les-Nancy F-54500, France CNRS, UMR 7565, Vandoeuvre-les-Nancy F-54506, France 10.3762/bjoc.12.39 Abstract Efficient routes were developed for the diastereoselective synthesis of new O

• derivatives, bearing an arm terminated either with a hydroxy group or a fluorine atom, could be interesting candidates for diastereoisomeric intermediates and biological evaluations, especially for PET imaging experiments. Keywords: C-branched; diastereoselective; fluoroinositols; inositols; O-alkylated

• of inositols. The above results demonstrate that the new O-alkylated and C-branched inositols with myo- and scyllo-configuration were available in a highly diastereoselective way. Different types of arm were easily introduced on the inositol ring. For the O-alkylated series, the hydroxylated (myo-1

Diastereoselective Ugi reaction of chiral 1,3-aminoalcohols derived from an organocatalytic Mannich reaction

• Samantha Caputo,
• Andrea Basso,
• Lisa Moni,
• Renata Riva,
• Valeria Rocca and
• Luca Banfi

Beilstein J. Org. Chem. 2016, 12, 139–143, doi:10.3762/bjoc.12.15

• simpler variants) [10][11][12]. On the other hand, diastereoselective reactions using at least one chiral component are troublesome. Chiral isocyanides and chiral carboxylic acids invariably afford nearly 1:1 mixtures. α-Chiral aldehydes have a high tendency to racemize/epimerize [13][14] and additionally

• , no report of valuable diastereocontrol by them has appeared so far. Successful examples of diastereoselective Ugi reactions have been reported only with chiral amines [15][16][17][18][19] or with chiral cyclic imines (Ugi–Joullié reaction) [20][21][22][23], although in the latter case, racemization

• , the usefulness of this approach relies on an efficient and diversity-oriented preparation of the required amines in high enantiomeric excess. Chiral aminoalcohols can be ideal substrates for diastereoselective Ugi reactions: the additional hydroxy group can both help in modulating diastereoselectivity

Copper-catalyzed intermolecular oxyamination of olefins using carboxylic acids and O-benzoylhydroxylamines

• Brett N. Hemric and
• Qiu Wang

Beilstein J. Org. Chem. 2016, 12, 22–28, doi:10.3762/bjoc.12.4

• results suggest a contribution of the structural conformation to the diastereoselective outcome of the reaction. Yet, 1,1-disubstituted olefins were not effective, likely due to the increased steric hindrance in the oxygenation step (Table 2, entry 12). Currently, the mechanistic details of this copper

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

• Chemical Ltd., was chosen as a key building block to be condensed with 2 to form the imine. The reaction in the presence of Ti(OEt)4 gave compound 4 in 78% yield [14] (Scheme 1). The diastereoselective reduction of imine 4 (Scheme 2) was the key step in this route. Accordingly, various conditions were

Recent advances in copper-catalyzed asymmetric coupling reactions

• Fengtao Zhou and
• Qian Cai

Beilstein J. Org. Chem. 2015, 11, 2600–2615, doi:10.3762/bjoc.11.280

• ] synthesized the natural product kotanin. Coleman and Grant [35] described an efficient synthesis of calphostin A, a potent protein kinase C inhibitor. In 2002, Marinetti et al. [36][37] employed this approach to prepare biaryl diphosphines. In 2004, Chan et al. [38] also developed a diastereoselective

• -permethyl-tellimagrandin I. Total synthesis of (+)-gossypol. Total synthesis of (−)-mastigophorene A. Total synthesis of isokotanin. Synthesis of dimethyl[7]thiaheterohelicenes. Intramolecular coupling with chiral ortho-substituents. Chiral 1,3-diol-derived tethers in the diastereoselective synthesis of

Organocatalytic and enantioselective Michael reaction between α-nitroesters and nitroalkenes. Syn/anti-selectivity control using catalysts with the same absolute backbone chirality

• Jose I. Martínez,
• Uxue Uria,
• Maria Muñiz,
• Efraím Reyes,
• Luisa Carrillo and
• Jose L. Vicario

Beilstein J. Org. Chem. 2015, 11, 2577–2583, doi:10.3762/bjoc.11.277

• ethyl 2-nitropropanoate and β-nitrostyrene as model substrates. Proposed models to explain the stereochemical outcome of the reaction. Enantio- and diastereoselective Michael reaction between nitroesters 1 and nitroalkenes 2 catalysed by 4.a Enantio- and diastereoselective Michael reaction between

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

• aldehyde 67 in six steps in 34% yield. After saponification of the ester functionality, treatment with tosyl chloride and trimethylamine resulted in the formation of a ketene that underwent a diastereoselective intramolecular [2 + 2] cycloaddition to provide bicyclic ketone 69. Addition of TMS cerium

• construction of the cyclononene unit [49]. The synthesis started with a diastereoselective Evans syn-aldol reaction between substituted propanal 86 and E-crotonyl-oxazolidinone 85 (Scheme 9). The resulting secondary alcohol was silylated and the chiral auxiliary was cleaved with lithium borohydride. Acylation

Synthesis of D-fructose-derived spirocyclic 2-substituted-2-oxazoline ribosides

• Madhuri Vangala and
• Ganesh P. Shinde

Beilstein J. Org. Chem. 2015, 11, 2289–2296, doi:10.3762/bjoc.11.249

• nucleophilic substitution at the anomeric center by vicinal participation of the C2 acylamino group. These are highly reactive and favor the formation of 1,2-trans-glycosides in a diastereoselective fashion [23][24][25][26]. Secondly, the C1 N-linked 1,2-glycooxazolines (Figure 1, 5) are derived from either

Synthesis of constrained analogues of tryptophan

• Elisabetta Rossi,
• Valentina Pirovano,
• Marco Negrato,
• Giorgio Abbiati and
• Monica Dell’Acqua

Beilstein J. Org. Chem. 2015, 11, 1997–2006, doi:10.3762/bjoc.11.216

• -catalysed diastereoselective [4 + 2] cycloaddition of vinylindoles and methyl 2-acetamidoacrylate, leading to methyl 3-acetamido-1,2,3,4-tetrahydrocarbazole-3-carboxylate derivatives, is described. Treatment of the obtained cycloadducts under hydrolytic conditions results in the preparation of a small

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

• synthesis of fused medium-sized rings has been reported by Ghosh and co-workers [41] via a sequential diastereoselective DA reaction and a RRM protocol. A variety of sugar-based norbornene derivatives provide an entry to various functionalized bicyclic sugar derivatives containing 7–9 membered rings. To

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• components, decarboxylative arylations of amino acids, diastereoselective preparations of cis-cyclobutanes via [2 + 2] cycloadditions of enones, selective reductions of benzylic and α-carbonyl halides and, with fac-Ir(ppy)3, reductions of unactivated alkyl iodides [5][6][7][8]. Furthermore, the value of

The enantioselective synthesis of (S)-(+)-mianserin and (S)-(+)-epinastine

• Piotr Roszkowski,
• Jan. K. Maurin and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2015, 11, 1509–1513, doi:10.3762/bjoc.11.164

• mianserin was originally described by Organon [4][5], and in 1999 Jackson and Subasinghe presented a method for the separation of mianserin enantiomers with (+)- or (−)-di-p-toluoyltartaric acid [6]. Later, the diastereoselective synthesis of (R)-mianserin using (S)-(−)-α-methylbenzylamine as a chiral

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• underdeveloped due to their inherently low reactivity. This review highlights the work that has been done on both diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams. Keywords: α,β-unsaturated amides; α,β-unsaturated lactams; conjugate addition

• done on the development of diastereoselective and enantioselective conjugate addition reactions using α,β-unsaturated amides and lactams. This is not an exhaustive account of all ACA reactions that employ α,β-unsaturated amides and lactams as Michael acceptors. Instead, the review aims to highlight

• review. 1 Diastereoselective conjugate additions (DCA) Though CA reactions had been studied for decades, significant progress in the development of CA reactions using α,β-unsaturated amides and lactams was not observed until the 1980s [28][29][30][31]. Initial efforts toward performing the asymmetric CA

Electrochemical selenium- and iodonium-initiated cyclisation of hydroxy-functionalised 1,4-dienes

• Philipp Röse,
• Steffen Emge,
• Jun-ichi Yoshida and
• Gerhard Hilt

Beilstein J. Org. Chem. 2015, 11, 174–183, doi:10.3762/bjoc.11.18

• 10.3762/bjoc.11.18 Abstract The cobalt(I)-catalysed 1,4-hydrovinylation reaction of allyloxytrimethylsilane and allyl alcohol with substituted 1,3-dienes leads to hydroxy-functionalised 1,4-dienes in excellent regio- and diastereoselective fashion. Those 1,4-dienols can be converted into tetrahydrofuran

• cyclisation in moderate to good yields. The products were generated in diastereoselective fashion and the configuration of the formed diastereomer could be identified by 1H NMR experiments comparing a mixture of both diastereomers, synthesised by conventional selenoalkoxylation, with the electrochemically

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• stainless steel cathode were utilised in a flow cell set-up [35]. An important example of the scope and synthetic potential of the silyl electroauxiliary approach was reported by Yoshida (Scheme 5) in combination with a chiral auxiliary a highly diastereoselective cationic carbohydroxylation occurred [18

• -carbon bonds [11]. The influence of the amino protecting group on the “kinetic” and “thermodynamic” anodic methoxylation [16]. Example of the application of the cation pool method [17]. A thiophenyl electroauxiliary allows for regioselective anodic oxidation [32]. A diastereoselective cation

Inherently chiral calix[4]arenes via oxazoline directed ortholithiation: synthesis and probe of chiral space

• Simon A. Herbert,
• Laura J. van Laeren,
• Dominic C. Castell and
• Gareth E. Arnott

Beilstein J. Org. Chem. 2014, 10, 2751–2755, doi:10.3762/bjoc.10.291

• Simon A. Herbert Laura J. van Laeren Dominic C. Castell Gareth E. Arnott Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa 10.3762/bjoc.10.291 Abstract The diastereoselective oxazoline-directed lithiation of calix[4]arenes is

• reported with diastereoselective ratios of greater than 100:1 in some instances. Notably, it has been found that the opposite diastereomer can be accessed via this approach merely through the choice of an alkyllithium reagent. The inherently chiral oxazoline calix[4]arenes have also been preliminarily

• of diastereomers was found to be opposite to those obtained when using the other alkyllithiums. Indeed diastereoselective reversals of this type have only rarely been observed in the literature [28][29][30][31] but importantly offer the advantage of accessing both inherently chiral antipodes after

Preparation of neuroprotective condensed 1,4-benzoxazepines by regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction

• László Tóth,
• Yan Fu,
• Hai Yan Zhang,
• Attila Mándi,
• Katalin E. Kövér,
• Tünde-Zita Illyés,
• Attila Kiss-Szikszai,
• Balázs Balogh,
• Tibor Kurtán,
• Sándor Antus and
• Péter Mátyus

Beilstein J. Org. Chem. 2014, 10, 2594–2602, doi:10.3762/bjoc.10.272

• Chemistry, University of Debrecen, H-4010 Debrecen, Hungary Porfirin Ltd., Mikszáth K. u. 7. III/3, 4032 Debrecen, Hungary 10.3762/bjoc.10.272 Abstract Condensed O,N-heterocycles containing tetrahydro-1,4-benzoxazepine and tetrahydroquinoline moieties were prepared by a regio- and diastereoselective domino

• cellular injuries in human neuroblastoma SH-SY5Y cells in the range of those of positive controls. Keywords: 1,4-benzoxazepine; diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization; neuroprotective; tert-amino effect; TDDFT-ECD calculation; Introduction The 1,4-benzoxazepine structural

• neuroprotective condensed 2-phenyl-1,4-benzoxazepines rac-7a,b through the diastereoselective domino Knoevenagel–1,5-hydride shift cyclization reaction rac-5→rac-7a,b from the readily available 4-aryl-2-phenyl-1,4-benzoxazepine derivative, rac-5 (Scheme 1). Ring-closure transformations involving C(sp3)–H bond

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

• aminoglycosides [7], and nucleosides containing 9H-purin-6-amine as a nucleobase portion. High levels of stereoselectivity have been observed in substrate-controlled diastereoselective epoxidation of cyclic alkenes with O- and N-allylic directing groups [20][21]. Several 3-substituted diastereomeric epoxides have

Formal total syntheses of classic natural product target molecules via palladium-catalyzed enantioselective alkylation

• Yiyang Liu,
• Marc Liniger,
• Ryan M. McFadden,
• Jenny L. Roizen,
• Jacquie Malette,
• Corey M. Reeves,
• Douglas C. Behenna,
• Masaki Seto,
• Jimin Kim,
• Justin T. Mohr,
• Scott C. Virgil and
• Brian M. Stoltz

Beilstein J. Org. Chem. 2014, 10, 2501–2512, doi:10.3762/bjoc.10.261

• chiral glycolic acid ketal 23 (enantioenriched to 80% ee) to the more elaborate diene 24 via two diastereoselective alkylations. After a sequence of three reactions including removal of the pinacolone portion of the auxiliary, carboxylic acid 22 could be accessed. Novak’s synthesis applied a

• of which are enantioselective [54][55][56]. In Danishefsky’s approach to racemic dysidiolide, the cyclohexene ring of 30 was installed via diastereoselective Diels–Alder reaction of a transient dioxolenium dienophile and chiral vinylcyclohexene 31 [48]. Triene 31 was prepared from α-quaternary ketone

Total synthesis of the proposed structure of astakolactin

• Takayuki Tonoi,
• Keisuke Mameda,
• Moe Fujishiro,
• Yutaka Yoshinaga and
• Isamu Shiina

Beilstein J. Org. Chem. 2014, 10, 2421–2427, doi:10.3762/bjoc.10.252

• ethyl acetate to afford the adduct 19. Diastereoselective methylation of the ester enolate moiety of 19 with MeI afforded only the anti-product 20 [32][33], which was then subjected to the deprotection of the TBDPS group with HF·pyridine, followed by cleavage of the ethyl ester group in 21 to give the

A modular phosphate tether-mediated divergent strategy to complex polyols

• Paul R. Hanson,
• Susanthi Jayasinghe,
• Soma Maitra,
• Cornelius N. Ndi and
• Rambabu Chegondi

Beilstein J. Org. Chem. 2014, 10, 2332–2337, doi:10.3762/bjoc.10.242

• diastereoselective reactions including one-pot, sequential RCM/CM/H2 protocols and their applications in total synthesis of various natural products [27][28][29][30][31][32]. In addition, the scope of phosphate-tethered methods was further expanded via extensive RCM studies of different triene subunits utilizing