A convenient enantioselective decarboxylative aldol reaction to access chiral α-hydroxy esters using β-keto acids

• Zhiqiang Duan,
• Jianlin Han,
• Ping Qian,
• Zirui Zhang,
• Yi Wang and
• Yi Pan

Beilstein J. Org. Chem. 2014, 10, 969–974, doi:10.3762/bjoc.10.95

• and aliphatic α-keto esters. The possible mechanism is rationalized. Keywords: enantioselective synthesis; hydroxy esters; scandium; Introduction The catalytic enantioselective construction of tertiary carbon centres is a major challenge in organic chemistry. The nucleophilic attack of carbonyls

Primary-tertiary diamine-catalyzed Michael addition of ketones to isatylidenemalononitrile derivatives

• Akshay Kumar and
• Swapandeep Singh Chimni

Beilstein J. Org. Chem. 2014, 10, 929–935, doi:10.3762/bjoc.10.91

• attention as novel substrates for the enantioselective synthesis of 3,3'-disubstituted oxindoles [18][19][20][21][22]. The organocatalytic Michael addition of ketones to isatylidenemalononitriles via enamine-catalysis has emerged as a useful tool for the synthesis of 3,3'-disubstituted oxindoles, which

Aza-Diels–Alder reaction between N-aryl-1-oxo-1H-isoindolium ions and tert-enamides: Steric effects on reaction outcome

• Amitabh Jha,
• Ting-Yi Chou,
• Zainab ALJaroudi,
• Bobby D. Ellis and
• T. Stanley Cameron

Beilstein J. Org. Chem. 2014, 10, 848–857, doi:10.3762/bjoc.10.81

• and strongly basic conditions [19]. Kang et al. achieved a highly enantioselective synthesis of an isoindolo[2,1-a]quinoline derivative by affecting an intramolecular ring closure on (E)-3-(2-(isoindolin-2-yl)phenyl)acrylaldehyde using camphorsulfonic acid and a chiral pyrrolidine organocatalyst [20

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

• Wageningen, The Netherlands 10.3762/bjoc.10.71 Abstract Virgin females of the parasitoid wasp Trichogramma turkestanica produce minute amounts of a sex pheromone, the identity of which has not been fully established. The enantioselective synthesis of a putative component of this pheromone, (6S,8S,10S

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

Organocatalytic asymmetric fluorination of α-chloroaldehydes involving kinetic resolution

• Kazutaka Shibatomi,
• Takuya Okimi,
• Yoshiyuki Abe,
• Akira Narayama,
• Nami Nakamura and
• Seiji Iwasa

Beilstein J. Org. Chem. 2014, 10, 323–331, doi:10.3762/bjoc.10.30

• the fluorination of α-branched aldehydes [7]. During the course of our study on the enantioselective construction of such fluorinated stereogenic centers, we developed a method for the enantioselective synthesis of α-chloro-α-fluoroaldehydes via the organocatalytic α-fluorination of α-alkyl-α

• (Scheme 1) [8]. These results suggested that kinetic resolution of the starting aldehydes was involved in this asymmetric fluorination. To collect further information on the reaction mechanism, we sought to determine the absolute configuration of 4a. Recently, we reported the enantioselective synthesis of

New developments in gold-catalyzed manipulation of inactivated alkenes

• Michel Chiarucci and
• Marco Bandini

Beilstein J. Org. Chem. 2013, 9, 2586–2614, doi:10.3762/bjoc.9.294

• anti-elimination was invoked to account for the observed experimental outcome (Scheme 29d). A complementary approach for the enantioselective synthesis of 3,4-disubstituted pyrrolidines was recently reported by Bandini and co-workers [72]. Intramolecular hydroalkylation of allylic alcohols with

A combined continuous microflow photochemistry and asymmetric organocatalysis approach for the enantioselective synthesis of tetrahydroquinolines

• Erli Sugiono and
• Magnus Rueping

Beilstein J. Org. Chem. 2013, 9, 2457–2462, doi:10.3762/bjoc.9.284

Towards stereochemical control: A short formal enantioselective total synthesis of pumiliotoxins 251D and 237A

• Jie Zhang,
• Hong-Kui Zhang and
• Pei-Qiang Huang

Beilstein J. Org. Chem. 2013, 9, 2358–2366, doi:10.3762/bjoc.9.271

• , Lanzhou 730000, P. R. China 10.3762/bjoc.9.271 Abstract A concise enantioselective synthesis of the advanced intermediate 5 for the synthesis of pumiliotoxins (Gallagher’s intermediate) is described. The synthesis started from the regio- and trans-diastereoselective (dr = 98:2) reductive 3-butenylation

• consisting of ozonolysis and reductive dehydroxylation provided the indolizidine derivative 5, which completed the formal enantioselective total synthesis of pumiliotoxins 251D and 237A. Keywords: enantioselective synthesis; Grignard reagent; pumiliotoxin 237A; pumiliotoxin 251D; reductive dehydroxylation

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• R-(+) form, the S-(−) form or the racemate leading to the conclusion that an enantioselective synthesis leading to solely S-(−)-amlodipine would be beneficial only if economically feasible [67]. An alternative strategy to this molecule begins with an interesting aza-Diels–Alder reaction between the

• racemic quinuclidinol. However, an improved approach makes use of a Noyori-type asymmetric reduction employing a BINAP ligated RuCl2 and a chiral diamine to yield the desired (R)-quinuclidine in high yield and enantioselectivity [78]. The enantioselective synthesis of the tetrahydroisoquinoline fragment

Gold(I)-catalyzed enantioselective cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2013, 9, 2250–2264, doi:10.3762/bjoc.9.264

• (Scheme 1). In 2009, the same group extended the utility of this asymmetric cyclopropanation reaction to an intramolecular process that allows the enantioselective synthesis of polycarbocyclic products embedding seven or eight-membered rings [42]. Curiously, the catalytic system based on DTBM-Segphos

• core of frondosins (for example, 5a), in 68% yield and 90% ee (Scheme 4). Since this bicyclic enone was previously elaborated into frondosin A and B, the approach represented a streamlined formal enantioselective synthesis of both molecules. Analogous to other transition metals from groups eight to

Synthesis of enantiomerically pure N-(2,3-dihydroxypropyl)arylamides via oxidative esterification

• Akula Raghunadh,
• Satish S More,
• T. Krishna Chaitanya,
• Yadla Sateesh Kumar,
• Suresh Babu Meruva,
• L. Vaikunta Rao and
• U. K. Syam Kumar

Beilstein J. Org. Chem. 2013, 9, 2129–2136, doi:10.3762/bjoc.9.250

• to facilitate these reactions [10][11][12][13][14][15][16][17][18]. Herein we describe a highly enantioselective synthesis of (S) and (R)-N-(2,3-dihydroxypropyl)arylamides [19][20][21][22] in a two-step process in overall good yields by oxidative esterification of the corresponding aryl aldehydes

• purifications and showed a chiral HPLC purity of 100% with retention of configuration. Conclusion A highly enantioselective synthesis of (S) and (R)-isomers of N-(2,3-dihydroxypropyl)arylamides was developed with high overall yields. We report the nitrogen heterocyclic carbene catalyzed enantioselective ring

A concise enantioselective synthesis of the guaiane sesquiterpene (−)-oxyphyllol

• Martin Zahel and
• Peter Metz

Beilstein J. Org. Chem. 2013, 9, 2028–2032, doi:10.3762/bjoc.9.239

• ; Introduction The hydroazulene framework is present in many natural products that are often associated with interesting biological properties [1][2]. The guaiane sesquiterpene (−)-oxyphyllol (1) has been isolated from the roots of the Thai medicinal plant Phyllanthus oxyphyllus [3]. A recent enantioselective

• synthesis of the unnatural enantiomer of 1 enabled a structural revision of this compound and established its relative and absolute configuration as depicted in Figure 1 [4]. During the total synthesis of (−)-9-deoxyenglerin A, compound 1 had already been prepared enantiomerically pure in 14 steps starting

Enantioselective synthesis of planar chiral ferrocenes via palladium-catalyzed annulation with diarylethynes

• Yan-Chao Shi,
• Rong-Fei Yang,
• De-Wei Gao and
• Shu-Li You

Beilstein J. Org. Chem. 2013, 9, 1891–1896, doi:10.3762/bjoc.9.222

• highly enantioselective synthesis of planar chiral ferrocenes via palladium-catalyzed direct annulation of N,N-disubstituted aminomethylferrocene derivatives with diarylethynes. The commercially available N-Boc-L-Val-OH is an efficient ligand with air as a suitable oxidant. The planar chiral ferrocenes

• could be transformed readily into a P,N-ligand, which was found to be suitable for Pd-catalyzed allylic substitution reactions. Experimental General procedure for the enantioselective synthesis of planar chiral ferrocenes To a solution of alkyne 2 (0.46 mmol) in DMA (1.5 mL) was added Boc-L-Val-OH (8.7

• . Enantioselective synthesis of planar chiral ferrocenes via C–H activationa. Supporting Information Supporting Information File 342: Experimental, characterization data and spectra. Acknowledgements We thank the National Basic Research Program of China (973 Program 2010CB833300), the National Natural Science

Catalytic asymmetric tandem Friedel–Crafts alkylation/Michael addition reaction for the synthesis of highly functionalized chromans

• Jiahuan Peng and
• Da-Ming Du

Beilstein J. Org. Chem. 2013, 9, 1210–1216, doi:10.3762/bjoc.9.137

• its derivatives in previous reports [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. During the preparation of this manuscript, a similar report on the enantioselective synthesis of highly substituted chromans by a Zinc(II)-catalyzed tandem Friedel–Crafts alkylation/Michael addition

Synthesis of the tetracyclic core of Illicium sesquiterpenes using an organocatalyzed asymmetric Robinson annulation

• Lynnie Trzoss,
• Jing Xu,
• Michelle H. Lacoske and
• Emmanuel A. Theodorakis

Beilstein J. Org. Chem. 2013, 9, 1135–1140, doi:10.3762/bjoc.9.126

• Lynnie Trzoss Jing Xu Michelle H. Lacoske Emmanuel A. Theodorakis Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA 10.3762/bjoc.9.126 Abstract An enantioselective synthesis of the core framework of neurotrophic Illicium

• –Miescher ketones represent two of the most famous examples [59][60][61][62][63][64][65]. With this background information in mind, we devised an enantioselective synthesis of 8 starting from commercially available dione 12, and the synthesis of 8 was previously published [25][26]. Tsuji–Trost allylation

Facile synthesis of functionalized spiro[indoline-3,2'-oxiran]-2-ones by Darzens reaction

• Qin Fu and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2013, 9, 918–924, doi:10.3762/bjoc.9.105

• and enantioselective synthesis of versatile spiro-oxirane-oxindoles [14][15][16][17][18][19]. With the aim of expanding our previous studies on the synthesis of various spirooxindoles [20][21][22][23][24][25], we decided to systematically investigate the Darzens reactions of a series of isatins with

A versatile and efficient approach for the synthesis of chiral 1,3-nitroamines and 1,3-diamines via conjugate addition to new (S,E)-γ-aminated nitroalkenes derived from L-α-amino acids

• Vera Lúcia Patrocinio Pereira,
• André Luiz da Silva Moura,
• Daniel Pais Pires Vieira,
• Leandro Lara de Carvalho,
• Eliz Regina Bueno Torres and
• Jeronimo da Silva Costa

Beilstein J. Org. Chem. 2013, 9, 832–837, doi:10.3762/bjoc.9.95

• enantioselective synthesis as chiral auxiliaries, chiral catalysts, chiral reagents and chiral ligands [59][60]. In our continuing interest in synthesizing new chiral nonracemic nitro compounds [61][62][63][64][65][66][67][68] by a "chiron" approach [45], we intended to develop a route for obtaining γ-nitrogenated

Some aspects of radical chemistry in the assembly of complex molecular architectures

• Béatrice Quiclet-Sire and
• Samir Z. Zard

Beilstein J. Org. Chem. 2013, 9, 557–576, doi:10.3762/bjoc.9.61

• be easily constructed. Spiroketals 119 and 120 are two such examples. The former was used in the total enantioselective synthesis of (+)-broussonetine G (121) [50]. If one of the alkenes contains a masked aldehyde, a bis-spiroketal such as 122 may be accessed. Furthermore, placing a 1,2- or a 1,3

Asymmetric Diels–Alder reaction with >C=P– functionality of the 2-phosphaindolizine-η¹-P-aluminium(O-menthoxy) dichloride complex: experimental and theoretical results

• Rajendra K. Jangid,
• Nidhi Sogani,
• Neelima Gupta,
• Raj K. Bansal,
• Moritz von Hopffgarten and
• Gernot Frenking

Beilstein J. Org. Chem. 2013, 9, 392–400, doi:10.3762/bjoc.9.40

• developed [2]. The chiral pool continues to be an attractive and economic source of enantiomerically pure chiral auxiliaries (ligands or modifiers) for enantioselective synthesis [3]. Two naturally occurring enantiomers of menthol and synthetically prepared (1R)-(+)-8-phenylmenthol have often been used as

Reactions of salicylaldehyde and enolates or their equivalents: versatile synthetic routes to chromane derivatives

• Ishmael B. Masesane and
• Zelalem Yibralign Desta

Beilstein J. Org. Chem. 2012, 8, 2166–2175, doi:10.3762/bjoc.8.244

• 22 by Costa and co-workers. Costa and co-workers used Et3N in the synthesis of 2-aminochromene 24. Synthesis of 2-aminochromene 27 by Shanthi and co-workers. Enantioselective synthesis of 2-aminochromenes 32–34 by Yang and co-workers. Synthesis of 2-iminochromene derivatives of type 36 by Kovalenko

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

• : ball-milling; enantioselective synthesis; mechanochemistry; organocatalysis; solvent-free; Introduction Green chemistry involves innovation in chemical research and engineering that encourages the design of processes to minimize the use and production of hazardous materials and also reduce the use of

Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes

• Gianluigi Broggini,
• Egle M. Beccalli,
• Andrea Fasana and
• Silvia Gazzola

Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198

• -alkenylindoles in an atmosphere of molecular oxygen provided dihydroindoloazocine compounds that are key intermediates in the total synthesis of the austamide derivatives and the okaramine family of polycyclic bisindole alkaloids [73][74]. Enantioselective synthesis of vinyl-substituted tetrahydro-β-carbolines

• ]indole skeleton by intramolecular C-2 alkenylation. Synthesis of azepinoindoles by oxidative Heck cyclization. Enantioselective synthesis of 4-vinyl-substituted tetrahydro-β-carbolines. Pd-catalyzed endo-cyclization of 3-alkenylindoles for the construction of carbazoles. Pd-catalyzed hydroamination of 2

Organocatalytic cascade aza-Michael/hemiacetal reaction between disubstituted hydrazines and α,β-unsaturated aldehydes: Highly diastereo- and enantioselective synthesis of pyrazolidine derivatives

• Zhi-Cong Geng,
• Jian Chen,
• Ning Li,
• Xiao-Fei Huang,
• Yong Zhang,
• Ya-Wen Zhang and
• Xing-Wang Wang

Beilstein J. Org. Chem. 2012, 8, 1710–1720, doi:10.3762/bjoc.8.195

• heterocyclic compounds have been efficiently generated by means of organocatalytic domino reactions [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69]. In 2009 and 2010, List et al. and the Brière group both reported, separately, the enantioselective synthesis of 2