Versatile deprotonated NHC: C,N-bridged dinuclear iridium and rhodium complexes

• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 117–124, doi:10.3762/bjoc.12.13

• bulky N-substituents [1]. However the existence of stable NHCs was before postulated by Wanzlick et al. during the 1960s [2][3][4] and supported later by Öfele [5][6]. NHCs have become useful ligands in many transition metal-catalyzed reactions, stimulating the study of the unique features of the M–NHC

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• formation has become a landmark achievement in fluorine chemistry. This rapidly growing research field has been the subject of some excellent reviews. Our approach focuses exclusively on transition metal-catalyzed reactions that allow the introduction of –CFH2, –CF2H, –CnF2n+1 and –SCF3 groups onto sp

Organocatalyzed enantioselective desymmetrization of aziridines and epoxides

• Ping-An Wang

Beilstein J. Org. Chem. 2013, 9, 1677–1695, doi:10.3762/bjoc.9.192

• based on transition-metal catalyzed reactions has given rise to a variety of significant achievements both in academic and industrial chemistry [2][3]. Desymmetrization is the modification of a molecule which results in the loss of symmetry elements such as a mirror plane, a center of inversion or a

Iridium-catalyzed intramolecular [4 + 2] cycloadditions of alkynyl halides

• Andrew Tigchelaar and
• William Tam

Beilstein J. Org. Chem. 2012, 8, 1765–1770, doi:10.3762/bjoc.8.201

• examples of intramolecular TMC [4 + 2] cycloadditions of diene-tethered alkynes. Reaction pathways of alkynyl halides in transition-metal-catalyzed reactions. Synthesis of diene-tethered alkynyl halides 1c and 1e. Synthesis of diene-tethered alkynyl halide 1g. Unsuccessful cycloaddition attempts with

Access to pyrrolo-pyridines by gold-catalyzed hydroarylation of pyrroles tethered to terminal alkynes

• Elena Borsini,
• Gianluigi Broggini,
• Andrea Fasana,
• Chiara Baldassarri,
• Angelo M. Manzo and
• Alcide D. Perboni

Beilstein J. Org. Chem. 2011, 7, 1468–1474, doi:10.3762/bjoc.7.170

• -azepines. Keywords: C–C coupling; gold catalysis; homogeneous catalysis; nitrogen heterocycles; rearrangement; Introduction Intramolecular transition-metal-catalyzed reactions represent one of the most challenging routes for the preparation of heterocyclic compounds [1][2][3][4][5]. Methodologies

Bromine–lithium exchange: An efficient tool in the modular construction of biaryl ligands

• Laurence Bonnafoux,
• Frédéric R. Leroux and
• Françoise Colobert

Beilstein J. Org. Chem. 2011, 7, 1278–1287, doi:10.3762/bjoc.7.148

• stereoelectronic profile of a ligand. Most frequently, biaryls are prepared through transition metal-catalyzed reactions of suitable functionalized starting materials [17][18][19][20][21][22]. Although these methods are well established, alternatives are investigated in order to avoid expensive transition metals

Directed aromatic functionalization

• Victor Snieckus

Beilstein J. Org. Chem. 2011, 7, 1215–1218, doi:10.3762/bjoc.7.141

• insertion, the gates of the synthetic arena were spectacularly opened to the 2010 Nobel Prize chemistry and the general theme of transition metal-catalyzed reactions. Thus, the named reactions of Kumada–Corriu, Negishi, Suzuki–Miyaura, Stille and, most recently, Hiyama have all given new insights into how

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• (Scheme 59) [174]. The first step is supposed to be an intramolecular addition of the hydroxy group to the internal carbon of the triple bond, which is similar to the mechanism mentioned above [161][163]. 6 Gold-catalyzed asymmetric addition reactions The chiral ligand used for the transition metal

• -catalyzed reactions are the main determinant of enantioselectivity. Although asymmetric catalysis using chiral organometal complexes and chiral organomolecules have shown many advantages and a range of catalytic asymmetric reactions have been well documented [175], gold-catalyzed asymmetric addition

When cyclopropenes meet gold catalysts

• Frédéric Miege,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

• versatile reactivity in transition metal-catalyzed reactions [15]. As has been observed with other transition metals, the reactivity of cyclopropenes A in gold-catalyzed reactions is essentially (but not exclusively) related to their ability to act as ligands for π-acidic gold complexes, and hence, to

• , depending on the substitution pattern [35][36]. Due to their high strain and π-electron density, cyclopropenes exhibit reactivity often comparable to that of alkynes in transition metal-catalyzed reactions. Not surprisingly, the reactivity of cyclopropenylmethyl carboxylates in the presence of gold

Gold-catalyzed heterocyclizations in alkynyl- and allenyl-β-lactams

• Benito Alcaide and
• Pedro Almendros

Beilstein J. Org. Chem. 2011, 7, 622–630, doi:10.3762/bjoc.7.73

• metal-catalyzed reactions of α-allenols which afford heterocyclization products, intramolecular cyclizations of γ-allenols have also attracted a great deal of interest [45][46][47]. A study of the regioselectivity control during the gold-catalyzed O–C functionalization of 2-azetidinone-tethered γ

• was catalyzed by gold salts (AuCl3), allene cycloisomerization adducts 7 were obtained as the sole isomers (Scheme 3). The cyclization of allenyl-β-lactams 5 is an application of the previously reported gold-catalyzed cycloisomerization of α-hydroxyallenes [42][43][44]. Similarly to the transition

Asymmetric reactions in continuous flow

• Xiao Yin Mak,
• Paola Laurino and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2009, 5, No. 19, doi:10.3762/bjoc.5.19

• (in the case of transition metal-catalyzed reactions) also can be problematic in large-scale syntheses, especially in pharmaceutical applications. Consequently, reactions based on the use of supported catalysts are in many ways a more attractive option for the stereoselective synthesis of chiral

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

• diastereoselectivity of transition metal catalyzed reactions of chiral substrates. This was accomplished by studying the diastereoselective Rh-catalyzed hydrogenation of the chiral allylic alcohol 1 and the homo-allylic alcohol 5. Since the goal was proof-of-principle, only 23 randomly chosen monodentate P-ligands

• conclusion, the previous concept of using mixtures of monodentate ligands in order to influence enantio-[19][20][21][22][23][24][25][26] and regioselectivity [28] of transition metal catalyzed reactions has been extended to include diastereoselectivity. The idea of using mixtures of monodentate ligands in a

• combinatorial manner is rapidly emerging as a powerful method to enhance activity and selectivity of transition metal-catalyzed reactions. Diastereoselective hydrogenation of the allylic alcohol 1. Diastereoselective hydrogenation of the homo-allylic alcohol 5. Acknowledgements Generous support from the Fonds