Highly efficient gold(I)-catalyzed Overman rearrangement in water

• Dong Xing and
• Dan Yang

Beilstein J. Org. Chem. 2011, 7, 781–785, doi:10.3762/bjoc.7.88

• allylic trichloroacetimidates to allylic trichloroacetamides (Overman rearrangement) is a powerful and attractive strategy for the synthesis of allylic amines from readily available allylic alcohols [1][2]. This transformation can be conducted thermally at high temperatures or by transition metal

• catalysis under very mild conditions [3][4][5][6][7]. Asymmetric induction has been achieved with certain types of transition metal catalysts (e.g., palladium complexes) in combination with chiral ancillary ligands [8][9][10][11][12][13]. However, although a large number of late transition metal catalysts

Continuous flow hydrogenation using polysilane-supported palladium/alumina hybrid catalysts

• Hidekazu Oyamada,
• Takeshi Naito and
• Shū Kobayashi

Beilstein J. Org. Chem. 2011, 7, 735–739, doi:10.3762/bjoc.7.83

• and substantially increase production. We also recently reported novel transition metal catalysis involving the immobilization of Pd or Pt onto polysilane supports by the microencapsulation method [12]. The Pd catalyst (Pd/PSi) had high activity with no or very little leaching of Pd, and it could be

Unusual behavior in the reactivity of 5-substituted-1H-tetrazoles in a resistively heated microreactor

• Bernhard Gutmann,
• Toma N. Glasnov,
• Tahseen Razzaq,
• Walter Goessler,
• Dominique M. Roberge and
• C. Oliver Kappe

Beilstein J. Org. Chem. 2011, 7, 503–517, doi:10.3762/bjoc.7.59

• steel or Hastelloy coils are heated by conductive techniques. Through a series of control experiments, effects of homogeneous metal catalysis as a result of reactor corrosion, and heterogeneous catalytic effects derived from the large metal surface area in the microreactor environment (wall effects

Suzuki–Miyaura cross-coupling reaction of 1-aryltriazenes with arylboronic acids catalyzed by a recyclable polymer-supported N-heterocyclic carbene–palladium complex catalyst

• Guangming Nan,
• Fang Ren and
• Meiming Luo

Beilstein J. Org. Chem. 2010, 6, No. 70, doi:10.3762/bjoc.6.70

• , arylsulfonyl chlorides and arenediazonium salts with arylboronic acids that gave biaryls in good to excellent yields [28][31][32]. As part of our ongoing investigations aimed at the development of transition metal catalysis, we report here that the Suzuki–Miyaura cross-couplings of 1-aryltriazenes with

A thermally-induced, tandem [3,3]-sigmatropic rearrangement/[2 + 2] cycloaddition approach to carbocyclic spirooxindoles

• Kay M. Brummond and
• Joshua M. Osbourn

Beilstein J. Org. Chem. 2010, 6, No. 33, doi:10.3762/bjoc.6.33

• rearrangement of the propargyl acetate 9a using transition metal catalysis (AuCl3 10 mol %, toluene, 1 h, rt) led to hydrolysis of the allenyl acetate functionality. This densely functionalized alkylidene cyclobutene 10a is postulated to arise via the [2 + 2] cycloaddition reaction between the alkyne and the

A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis

• Magnus Rueping and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2010, 6, No. 6, doi:10.3762/bjoc.6.6

• % [Rh(cod)2]BF4, 4 mol% PPh3 and HBF4•OEt2 was necessary for sufficient reactivity; yet electron-rich and N-alkylated anilines react without a metal catalysis in the presence of catalytic amounts of HBF4 (Scheme 20). About the same time a Ru3(CO)12-catalyzed hydroarylation of anilines was reported as

• simultaneously, an acid-catalyzed ortho-arylation of aniline employing the strong Brønsted acid PhNH3B(C6F5)4•Et2O was developed by Bergman et al. indicating the close relationship between strong Brønsted acid- and transition-metal catalysis [70]. A double ortho-hydroarylation of anilines with styrenes was

• optical active ligands for enantioselective transition-metal catalysis (Scheme 22) [71]. To the best of our knowledge, efficient ortho-benzylations of anilines with benzyl alcohols as alkylating reagents have yet to be described [15]. Catalytic Friedel–Crafts allylations Allylated arenes represent

Can we measure catalyst efficiency in asymmetric chemical reactions? A theoretical approach

• Shaimaa El-Fayyoumy,
• Matthew H. Todd and
• Christopher J. Richards

Beilstein J. Org. Chem. 2009, 5, No. 67, doi:10.3762/bjoc.5.67

• chemistry [1]. Enormous progress has been made in recent years, most notably in homogenous transition metal catalysis, organocatalysis and enzyme-catalysed reactions. It is therefore surprising that there is no generally accepted measure for the effectiveness of a catalytic reaction. That is to say when we

DBFOX- Ph/metal complexes: Evaluation as catalysts for enantioselective fluorination of 3-(2-arylacetyl)-2-thiazolidinones

• Takehisa Ishimaru,
• Norio Shibata,
• Dhande Sudhakar Reddy,
• Takao Horikawa,
• Shuichi Nakamura and
• Takeshi Toru

Beilstein J. Org. Chem. 2008, 4, No. 16, doi:10.3762/bjoc.4.16

• ) ligands, Box-Ph [(S,S)-2,2'-isopropylidene-bis(4-phenyl-2-oxazoline)] and DBFOX-Ph [(R,R)-4,6-dibenzofurandiyl-2,2'-bis(4-phenyloxazoline)] [33][34][36]. As an extension of this study, we herein evaluate our DBFOX-Ph/metal catalysis for the enantioselective fluorination of 3-(2-arylacetyl)-2

• stirred overnight under the same fluorination conditions. Further studies to improve the enantioselectivity of DBFOX-Ph/metal catalysis in enantioselective fluorination are under way. Structures of DBFOX-Ph, Box-Ph and NFSI. Transition-State Structure for the DBFOX-Ph/Ni(II) Catalyzed Enantioselective

Expedient syntheses of the N-heterocyclic carbene precursor imidazolium salts IPr·HCl, IMes·HCl and IXy·HCl

• Lukas Hintermann

Beilstein J. Org. Chem. 2007, 3, No. 22, doi:10.1186/1860-5397-3-22

• involving a 1,5-dipolar electrocyclization is proposed. Background Imidazolylidene carbenes have been investigated as ligands in coordination chemistry, as powerful steering/controlling elements in transition-metal catalysis,[1][2] and more recently as metal-free catalysts for organic reactions[3][4]. Some

An exceptional P-H phosphonite: Biphenyl- 2,2'-bisfenchylchlorophosphite and derived ligands (BIFOPs) in enantioselective copper- catalyzed 1,4-additions

• T. Kop-Weiershausen,
• J. Lex,
• J.-M. Neudörfl and
• B. Goldfuss

Beilstein J. Org. Chem. 2005, 1, No. 6, doi:10.1186/1860-5397-1-6

• the phosphorus atoms in biphenyl-2,2'-bisfenchylphosphites (BIFOPs) founds the special suitability for BIFOP-H (3) as P-H phosphonite ligand in transition metal catalysis. This points to promising applications of 3 or analogue P-H ligands in enantioselective catalysis. X-ray crystal structure of BIFOP

Mixtures of monodentate P-ligands as a means to control the diastereoselectivity in Rh-catalyzed hydrogenation of chiral alkenes

• Manfred T. Reetz and
• Hongchao Guo

Beilstein J. Org. Chem. 2005, 1, No. 3, doi:10.1186/1860-5397-1-3

• new approach in the area of combinatorial asymmetric transition metal catalysis:[19][20] The use of mixtures of two chiral monodentate ligands La and Lb in metal catalysts of the type ML2, leading to two so-called homo-combinations and one hetero-combination which are in equilibrium with one another