Synthesis, characterization, and applicability of neutral polyhydroxy phospholane derivatives and their rhodium(I) complexes for reactions in organic and aqueous media

Efficient asymmetric hydrogenation of quinolines in neat water catalyzed by chiral cationic Ru-diamine complexes

The first highly effective and enantioselective hydrogenation of quinolines catalyzed by chiral cationic Ru-diamine complexes in undegassed water was developed.

Synthesis and Suzuki-Miyaura Cross-Coupling of Enantioenriched Secondary Potassium β-Trifluoroboratoamides: Catalytic, Asymmetric Conjugate Addition of Bisboronic Acid and Tetrakis(dimethylamino)diboron to α,β-Unsaturated Carbonyl Compounds

Enantioenriched potassium β-trifluoroboratoamides have been synthesized via an asymmetric, copper-catalyzed 1,4-addition of tetrahydroxydiboron (BBA) and tetrakis(dimethylamino)diboron to α,β-unsaturated amides. These dibora reagents provide access to the desired organotrifluoroborates using effective and atom economical sources of boron. The copper-catalyzed β-boration is extended to α,β-unsaturated ketones and esters. Desired potassium organotrifluoroborates are synthesized with yields up to 92% and enantiomeric ratios up to 98:2. The enantioenriched potassium β-trifluoroboratoamides are successfully cross-coupled with an array of aryl and heteroaryl chlorides in high yield with complete stereochemical fidelity as the transmetalation proceeds through an S_E2 mechanism via an open transition state.

C1 and C2-symmetric carbohydrate phosphorus ligands in asymmetric catalysis

Carbohydrates are increasingly used as starting materials for the synthesis of enantiopure ligands. They contain a considerable number of stereocenters, and compounds with all possible configurational combinations are readily available. This tutorial review focuses on ligands obtained by the introduction of phosphorus functionalities (mainly phosphinite, phosphite or phosphine) into a carbohydrate framework. They are classified according to their structural features. In this review, ligands are organised as C1 ligands with a pyranoside or furanoside structure, and C2 ligands. Particular attention is paid to water soluble ligands prepared from carbohydrates. General methods for the preparation of the ligands are presented in order to show how the backbones can be obtained from simple carbohydrates. The catalytic results obtained in commonly studied processes are presented in tables in order to facilitate the comparison between the ligands. The advantages and limitations of the use of ligands based on carbohydrates are discussed.

Design, Synthesis, and Chemistry of Sterically Nondemanding Primary Bisphosphines1

Design and synthesis of chelating bisphosphines functionalized with the smallest chemical unit "H" on the P(III) centers ((PH(2)CH(2))(2)CHCH(2)NHPh (4) and (PH(2)CH(2))(2)CHCONHPh (5)) are described. Studies demonstrating that no bulky chemical substituents are necessary to offer thermal/oxidative stability to the -PH(2) groups in 4 and 5 are described. The H atoms around the P(III) centers in 5 (or 4) concur limited/no steric influence, but yet the phosphines manifest high nucleophilicity to coordinate strongly with W(0) and Re(I). The studies include synthesis and X-ray structural characterization of an air-stable primary bisphosphine (5) and its transition-metal chemistry with W(CO)(6) and Re(CO)(5)Br to produce the complexes (eta(2)-(PH(2)CH(2))(2)CHCONHPh)W(CO)(4) (6) and (eta(2)-(PH(2)CH(2))(2)CHCONHPh)Re(CO)(3)Br (7), respectively.

C2-Symmetric Diphosphinite Ligands Derived from Carbohydrates. The Strong Influence of Remote Stereocenters on Asymmetric Rhodium-Catalyzed Hydrogenation

Modular ligands of C(2) symmetry (13a-e, 14a,b,d, and ent-9), systematically modified at positions 2 and 5, were easily prepared from d-glucosamine, D-glucitol, and tartaric acid, respectively. The application of these ligands in the rhodium-catalyzed hydrogenation of methyl acetamidoacrylate, methyl acetamidocinnamate, and dimethyl itaconate shows that both the configuration and the substituents at positions 2 and 5 of the tetrahydrofuran backbone have a strong influence on the enantioselectivty of the processes.

Synthesis of both enantiomers of a P-chirogenic 1,2-bisphospholanoethane ligand via convergent routes and application to rhodium-catalyzed asymmetric hydrogenation of CI-1008 (pregabalin)

Both enantiomers of a P-chirogenic 1,2-bisphospholanoethane ligand are synthesized via two convergent methods. The first method relies on the chiral alkylation of 1-((-)-menthoxy)phospholaneborane using a s-BuLi/(-)-sparteine derived chiral base. Only one enantiomer of the catalyst could be synthesized via this method because only one antipode of sparteine is available in nature. The second route relies on the combination of methylphosphine borane and a chiral 1,4-diol. Either enantiomer of the ligand can be synthesized via the second route from the appropriate enantiomer of the 1,4-diol. Asymmetric hydrogenation using catalyst precursor 36 on acetamidoacrylic acid derivatives provided modest to good enantioselectivity (77-95% ee) under low H(2) pressure (30 psi). Asymmetric hydrogenation of CI-1008 (pregabalin) precursors, 39 and 40, provided good enantioselectivities (92%) at high catalyst loading (1 mol %) and low pressure (30 psi). Enantiomeric excesses dropped sharply with catalyst loading at this pressure. Increasing the pressure of H(2) caused a significant increase in enantiomeric excess for low catalyst loading reactions. Several studies were undertaken to further investigate the enantioselectivity dependence on both pressure and catalyst loading.

A novel chiral ferrocenyl phosphine ligand from sugar: applications in Rh-catalyzed asymmetric hydrogenation reactions

[structure: see text] A new chiral ferrocenyl diphosphine ligand 3 was synthesized from readily available D-mannitol. Rh-complex with this ligand showed high enantioselectivity and reactivity in the asymmetric hydrogenation of dehydroamino acid derivatives and itaconic acid derivatives. Up to over 99% ee and 10 000 TON were achieved with this catalytic system.