New α- and β-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions

• Iveta Chena Tichá,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2019, 15, 830–839, doi:10.3762/bjoc.15.80

• well-explored strategy [2] which can be used to prepare various types of CD derivatives. Several examples of modified-CD derivatives with a catalytic nucleophilic center have been reported in the area of organocatalytic asymmetric reactions [11]. Initially, Kanagaraj et al. [16] used per-6-amino-β-CD

• alkaloids have never been prepared and tested in asymmetric organocatalysis. Thus, in this study, we investigated methods for attaching cinchona alkaloids to CD skeletons, and we assessed the enantiomeric excess of the resulting CD derivatives as organocatalysts in asymmetric reactions, specifically in the

• the decarboxylative asymmetric allylic amination of a Morita–Baylis–Hillman carbamate (10 mol % of catalyst, up to 75% ee, up to 76% isolated yield). We believe that these new CD derivatives comprising cinchona alkaloids will be suitable catalysts of other asymmetric reactions using them under green

Some mechanistic aspects regarding the Suzuki–Miyaura reaction between selected ortho-substituted phenylboronic acids and 3,4,5-tribromo-2,6-dimethylpyridine

• Piotr Pomarański,
• Piotr Roszkowski,
• Jan K. Maurin,
• Armand Budzianowski and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2018, 14, 2384–2393, doi:10.3762/bjoc.14.214

• auxiliaries. Therefore, the atropselective synthesis is an important synthetic approach pursued by many research groups [22][23][24][25][26]. In 2015 the first phosphoric acid-catalysed asymmetric reactions of 2-naphthols with quinone analogues were described, allowing an access to a class of sterically

D-Fructose-based spiro-fused PHOX ligands: synthesis and application in enantioselective allylic alkylation

• Michael R. Imrich,
• Jochen Kraft,
• Cäcilia Maichle-Mössmer and
• Thomas Ziegler

Beilstein J. Org. Chem. 2018, 14, 2082–2089, doi:10.3762/bjoc.14.182

• efficient catalysts in various asymmetric reactions, for instance allylic substitution and enantioselective hydrogenation [9]. They were also applied in the stereoselective synthesis of complex natural products [10][11][12]. PHOX ligands are nonsymmetrical ligands which can coordinate to a metal center

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• hypervalent iodine(III)-catalyzed functionalization of alkenes and asymmetric reactions using a chiral iodoarene are summarized. Keywords: asymmetric catalysis; functionalization of alkenes; hypervalent iodine(III); Introduction Hypervalent iodine(III) reagents, also named as λ3-iodanes, have been widely

• alkenes as well as some asymmetric reactions employing a chiral iodoarene. Review Dioxygenation of alkenes In 2009, Yan and co-workers reported an efficient catalytic method for the sulfonyloxylactonization of alkenoic acids (Scheme 2) [43], which employed catalytic amounts of hypervalent iodine(III

Copper-catalyzed asymmetric methylation of fluoroalkylated pyruvates with dimethylzinc

• Kohsuke Aikawa,
• Kohei Yabuuchi,
• Kota Torii and
• Koichi Mikami

Beilstein J. Org. Chem. 2018, 14, 576–582, doi:10.3762/bjoc.14.44

• asymmetric carbon–carbon bond forming reactions, providing efficiently α-trifluoromethylated tertiary alcohols in high enantioselectivities [9][10][11][12][13][14][15][16][17][18][19]. Over the past decade we have also investigated several catalytic asymmetric reactions using trifluoropyruvate as an

Syn-selective silicon Mukaiyama-type aldol reactions of (pentafluoro-λ⁶-sulfanyl)acetic acid esters with aldehydes

• Anna-Lena Dreier,
• Andrej V. Matsnev,
• Joseph S. Thrasher and
• Günter Haufe

Beilstein J. Org. Chem. 2018, 14, 373–380, doi:10.3762/bjoc.14.25

• results of formation of an aldol addition product from the reaction of an SF5-substituted acetmorpholide and p-nitrobenzaldehyde are promising, and successful asymmetric reactions may be expected. Newman projections of the syn- and the anti-diastereomeric aldol addition products. Silicon-mediated

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• dichlorination reaction occurred. Interestingly, in both cases, it was observed that far lower ee values were reached when replacing CF3SO2Cl by N-chlorosuccinimide, which highlighted its great compatibility with asymmetric reactions. Conclusion Trifluoromethanesulfonyl chloride is an inexpensive versatile

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

Synthesis of new pyrrolidine-based organocatalysts and study of their use in the asymmetric Michael addition of aldehydes to nitroolefins

• Alejandro Castán,
• Ramón Badorrey,
• José A. Gálvez and
• María D. Díaz-de-Villegas

Beilstein J. Org. Chem. 2017, 13, 612–619, doi:10.3762/bjoc.13.59

• reaction conditions [21]. For example, in secondary amine-catalysed asymmetric reactions a Brønsted acid additive was found to accelerate the formation of the enamine intermediate and thus to improve not only the reactivity but also the diastereoselectivity and enantioselectivity [22][23]. On the other

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• treatment with p-toluenesulfonic acid in acetone to give the diketone 245 (Scheme 68). Then, the latter underwent oxidative aromatization by treatment with Pd/C in p-cymene. The synthesized 1-indanone 246 was further converted to the cis-1-amino-2-indanol 247 and used as ligand for asymmetric reactions. A

Highly chemo-, enantio-, and diastereoselective [4 + 2] cycloaddition of 5H-thiazol-4-ones with N-itaconimides

• Shuai Qiu,
• Choon-Hong Tan and
• Zhiyong Jiang

Beilstein J. Org. Chem. 2016, 12, 2293–2297, doi:10.3762/bjoc.12.222

• excellent catalytic efficacy as demonstrated in a series of asymmetric reactions [18]. It was found that the reaction was completed after 48 hours, affording the desired [4 + 2] annulation adduct 3a in 55% yield with 64% ee. A significant amount of conjugate addition adduct led to the unsatisfactory

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• the main focus has been directed not only to the search for new efficient chiral catalysts, but also to the development of efficient pronucleophiles. This review highlights the utility and first examples of 1H-imidazol-4(5H)-ones and thiazol-4(5H)-ones as pronucleophiles in catalytic asymmetric

• reactions. Keywords: asymmetric catalysis; bifunctional catalysts; 1H-imidazol-4(5H)-ones; pronucleophiles; thiazol-4(5H)-ones; Introduction Asymmetric catalysis [1][2][3] constitutes a very powerful tool for the preparation of enantiomerically pure compounds [4]. Recent efforts in the field have been

Asymmetric α-amination of 3-substituted oxindoles using chiral bifunctional phosphine catalysts

• Qiao-Wen Jin,
• Zhuo Chai,
• You-Ming Huang,
• Gang Zou and
• Gang Zhao

Beilstein J. Org. Chem. 2016, 12, 725–731, doi:10.3762/bjoc.12.72

• novel amino acid-derived chiral bifunctional organophosphine catalysts, which have successfully applied to catalyze various asymmetric reactions [40][41]. As a general concept, a tertiary phosphine adds to an electrophilic reactant to form a zwitterion which serves as either a nucleophile or a Bronsted

(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

• importance and therefore many asymmetric reactions that could not be achieved, are now possible. There are many reactions catalyzed by L-proline, affording stereoselective products in high yields and enantiomeric excess, nevertheless there are many limitations. For that reason, it has emerged the need for

• the synthesis of new molecules that would have the same reactivity with L-proline in catalyzed asymmetric reactions and better properties. The combination of proline with other molecules to provide a catalytic system was exploited by Ramachary and co-workers in an enamine-based Michael reaction

Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors

• Ming-Liang Zhang,
• Deng-Feng Yue,
• Zhen-Hua Wang,
• Yuan Luo,
• Xiao-Ying Xu,
• Xiao-Mei Zhang and
• Wei-Cheng Yuan

Beilstein J. Org. Chem. 2016, 12, 295–300, doi:10.3762/bjoc.12.31

• demonstrated to be an effective and versatile strategy in facilitating a variety of organic transformations over the past decade, and numerous catalytic asymmetric reactions have been developed with various activation modes [1][2][3][4][5][6]. In this realm, chiral bifunctional catalysts, possessing two active

• enantioselectivity (up to 73% ee). A possible transition-state model, characterized by the bifunctional catalyst acting as a multiple hydrogen-bond donor, is also proposed. The application of 1H-pyrrole-2,3-diones in the catalytic asymmetric reactions for the preparation of biologically relevant compounds is

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

• asymmetric reactions [19][20]. Recently, we disclosed an α-hydroxylation of tetralone-derived β-keto esters 2 using guanidine–bisurea bifunctional organocatalyst 1a in the presence of cumene hydroperoxide (CHP) as an oxidant (Figure 1a) [21]. This reaction provides the corresponding α-hydroxylation products

Copper-catalysed asymmetric allylic alkylation of alkylzirconocenes to racemic 3,6-dihydro-2H-pyrans

• Emeline Rideau and
• Stephen P. Fletcher

Beilstein J. Org. Chem. 2015, 11, 2435–2443, doi:10.3762/bjoc.11.264

• ) and TMSCl equivalent (0, 1 and 5) (Table S1, entries 18–30, ♦). As mixed results were obtained with Et2O, we decided to investigate it more thoroughly. This second study emphasizes the intrinsic challenge of finding optimum conditions in complex asymmetric reactions. Whereas CuOTf seems to work best

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

• enantioselectivities than phosphine ligands in rhodium-catalyzed asymmetric reactions [152][153]. Scheme 16 shows the rhodium-catalyzed asymmetric 1,4-arylation that was developed by Lin and co-workers and the subsequent transformation to the GABAB receptor agonist, (R)-(−)-baclofen. Much of the work that has been

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• ][55][56][57][58][59][60][61]. Due to the nature of the reaction and ready availability of catalyst, these asymmetric reactions could be undertaken at the mole-scale (giving more than 100 g of product), with possibility of both catalyst recovery and reuse. The scalability of these reactions is first

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

• reactions have evolved relatively slowly. Indeed, very little research on chiral tertiary phosphine-catalyzed asymmetric reactions occurred prior to the year 2000 [19][20]. Over the last decade, however, and especially since 2005, considerable progress has been made in asymmetric phosphine catalysis. As a

• result, phosphine-catalyzed asymmetric reactions are now powerful and versatile tools for the construction of C–C, C–N, C–O, and C–S bonds and for the syntheses of functionalized carbocycles and heterocycles [11][13][14]. In offering a general account of this field, herein we summarize the major

• developments in nucleophilic chiral phosphine-catalyzed asymmetric reactions, including annulations of allenes, ketenes, alkynes, and Morita–Baylis–Hillman (MBH) carbonates with activated alkenes and imines, allylic substitution of MBH acetates and carbonates, Michael additions, γ-umpolung additions, and

P(O)R₂-directed Pd-catalyzed C–H functionalization of biaryl derivatives to synthesize chiral phosphorous ligands

• Rong-Bin Hu,
• Hong-Li Wang,
• Hong-Yu Zhang,
• Heng Zhang,
• Yan-Na Ma and
• Shang-dong Yang

Beilstein J. Org. Chem. 2014, 10, 2071–2076, doi:10.3762/bjoc.10.215

• . China 10.3762/bjoc.10.215 Abstract Chiral phosphorus ligands have been widely used in transition metal-catalyzed asymmetric reactions. Herein, we report a new synthesis approach of chiral biaryls containing a phosphorus moiety using P(O)R2-directed Pd-catalyzed C–H activation; the functionalized

New hydrogen-bonding organocatalysts: Chiral cyclophosphazanes and phosphorus amides as catalysts for asymmetric Michael additions

• Helge Klare,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2014, 10, 224–236, doi:10.3762/bjoc.10.18

• different substitution patterns on phosphorus and nitrogen from commercially available amines and PCl3. While achiral PIII/V-cyclodiphospazanes have been studied as ligands in transition-metal chemistry [22][23], only two examples of cyclodiphosphazanes as catalysts in asymmetric reactions are known

Synthesis of axially chiral gold complexes and their applications in asymmetric catalyses

• Yin-wei Sun,
• Qin Xu and
• Min Shi

Beilstein J. Org. Chem. 2013, 9, 2224–2232, doi:10.3762/bjoc.9.261

• . However, chiral gold complexes [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45], especially chiral NHC–gold complex-catalyzed asymmetric reactions [46][47][48][49][50][51][52][53] are still uncommon. Very few efficient chiral NHC–gold catalysts have been known up to the year of 2013. So

Mechanochemistry assisted asymmetric organocatalysis: A sustainable approach

• Pankaj Chauhan and
• Swapandeep Singh Chimni

Beilstein J. Org. Chem. 2012, 8, 2132–2141, doi:10.3762/bjoc.8.240

• catalysing asymmetric reactions may allow several advantages, such as lower toxicity compared to metal analogues, robustness, no requirement of an inert atmosphere, provision of high stereoselectivity, and the ability to be used for the synthesis of opposite enantiomers by using enantiomeric catalysts

• , which helps in the easy isolation of products. Besides the significant progress in the application of mechanochemical techniques in asymmetric organocatalysis, there exists a lot of scope for other asymmetric reactions ranging from simple carbon–carbon, and carbon–heteroatom bond formation to more

Asymmetric one-pot sequential Friedel–Crafts-type alkylation and α-oxyamination catalyzed by a peptide and an enzyme

• Kengo Akagawa,
• Ryota Umezawa and
• Kazuaki Kudo

Beilstein J. Org. Chem. 2012, 8, 1333–1337, doi:10.3762/bjoc.8.152

• diastereomer was 96% (Table 1, entry 1). It is noteworthy that the ee of the major diastereomer was higher than that of each single reaction [33][37]. Such enantio-enrichment is generally caused in consecutive catalytic asymmetric reactions through the formation of diastereomeric pairs [17][41]. From the