Sulfoxide Phosphine Research Articles

Enantioselective Double Carbonylation Enabled by High-Valent Palladium Catalysis.

Palladium-catalyzed carbonylation reactions are efficient methods for synthesizing valuable molecules. However, realizing a carbonylation with excellent yield and chemo-, regio-, and enantioselectivities by classical low-valent palladium catalysis is highly challenging. Herein, we describe an enantioselective carbonylation reaction using a high-valent palladium catalysis strategy and employing a chiral sulfoxide phosphine (SOP) ligand. This double aminocarbonylation reaction begins with the formation of a carbamoylpalladium(II) species, which undergoes enantioselective oxidative addition with a cyclic diaryliodonium salt to generate a palladium(IV) intermediate, followed by a second CO insertion and reductive elimination. The mechanism has been illustrated with experimental and computational studies.

Halogenated salt assisted Cu-catalyzed asymmetric 1,4-borylstannation of 1,3-enynes: enantioselective synthesis of allenylstannes.

An enantioselective 1,4-borylstannation of 1,3-enynes employed a chiral sulfoxide phosphine (SOP)/Cu complex as a catalyst, and the desired products, chiral allenylstannes, were first synthesized by asymmetric catalysis with satisfactory yields and enantioselectivies. In this protocol, a catalytic amount of additive, a halogenated salt, plays a crucial role in the success. Control experiments and theoretical studies disclosed that the four-membered ring transmetallation transition states which were stabilized by a halide anion are the key to yields and stereochemical outcomes.

Enantioselective Palladium-Catalyzed Hydrofluorination of Alkenylarenes

Hydrofluorination of simple alkenes is an attractive strategy to prepare fluorine-containing molecules. However, the catalytic asymmetric hydrofluorination remains an ongoing challenge. Here, we describe a palladium(II)-catalyzed enantioselective hydrofluorination of alkenylarenes, by employing sulfoxide phosphine (SOP) as a chiral ligand, triarylphosphine as a secondary ligand, Selectfluor as a fluorine source, and trihexylsilane as a hydride source. Under the optimal reaction conditions, a range of chiral benzyl fluorides bearing different functional groups are obtained in good yields (up to 80%) with high enantiopurity (having an enantiomeric ratio of up to 94:6). Some mechanistic insight of this reaction is obtained using in situ one- and two-dimensional 1H–31P HMBC nuclear magnetic resonance spectroscopy and a catalytic cycle is proposed.

Enantioselective Synthesis of Multisubstituted Allenes by Cooperative Cu/Pd‐Catalyzed 1,4‐Arylboration of 1,3‐Enynes

AbstractA cooperative Cu/Pd‐catalyzed enantioselective synthesis of multisubstituted allenes is established. By employing chiral sulfoxide phosphine (SOP)/Cu and PdCl2(dppf) complexes as catalysts, the 1,4‐arylboration of 1,3‐enynes provides an efficient approach to trisubstituted chiral allenes with up to 92 % yield and 97:3 er. Furthermore, by using 2‐substituted 1,3‐enynes as substrates, the tetrasubstituted chiral allenes were successfully generated using this strategy. Finally, theoretical calculations indicate that the transmetallation of the allenylcopper species is the rate‐limiting step of this transformation.

Enantioselective Synthesis of Multisubstituted Allenes by Cooperative Cu/Pd-Catalyzed 1,4-Arylboration of 1,3-Enynes.

A cooperative Cu/Pd-catalyzed enantioselective synthesis of multisubstituted allenes is established. By employing chiral sulfoxide phosphine (SOP)/Cu and PdCl2 (dppf) complexes as catalysts, the 1,4-arylboration of 1,3-enynes provides an efficient approach to trisubstituted chiral allenes with up to 92 % yield and 97:3 er. Furthermore, by using 2-substituted 1,3-enynes as substrates, the tetrasubstituted chiral allenes were successfully generated using this strategy. Finally, theoretical calculations indicate that the transmetallation of the allenylcopper species is the rate-limiting step of this transformation.

Modular Synthesis of Enantioenriched 1,1,2-Triarylethanes by an Enantioselective Arylboration and Cross-Coupling Sequence

An enantioselective Cu/Pd-catalyzed borylative coupling of styrenes with aryl/alkenyl iodides was realized using a chiral sulfoxide-phosphine (SOP) ligand. Enantioenriched 1,1-diarylethyl and β-aryl-homoallylic boronates are readily prepared. A streamlined procedure merging arylboration and subsequent Pd-catalyzed Suzuki–Miyaura cross-coupling enables the modular assembly of enantioenriched 1,1,2-triarylethanes, including two medicinally important chiral small-molecule targets.

Copper-Catalyzed Enantioselective Aminoboration of Styrenes with Chiral Sulfoxide Phosphine Ligand

Copper-Catalyzed Enantioselective Aminoboration of Styrenes with Chiral Sulfoxide Phosphine Ligand

ChemInform Abstract: Copper‐Catalyzed Enantioselective Conjugate Addition of Diethylzinc to Acyclic Enones with Chiral Sulfoxide—Phosphine Ligands.

AbstractThe enantioselective conjugate addition of diethylzinc to enones (I) leads to ketones (III) in low to moderate yields and with good to high enantioselectivities.

Copper-catalyzed enantioselective conjugate addition of diethylzinc to acyclic enones with chiral sulfoxide–phosphine ligands

The copper-catalyzed enantioselective conjugate addition of diethylzinc to acyclic enones was achieved with chiral sulfoxide–phosphine (SOP) ligands. This process showed good functional group tolerance and gave the 1, 4-adducts with excellent enantioselectivities (up to 96% ee).

ChemInform Abstract: Copper(I)‐Catalyzed Asymmetric Pinacolboryl Addition of N‐Boc‐imines Using a Chiral Sulfoxide—Phosphine Ligand.

AbstractThe title ligand SOP is highly efficient for the preparation of both enantiomers.

ChemInform Abstract: Rational Design of Sulfoxide—Phosphine Ligands for Pd‐Catalyzed Enantioselective Allylic Alkylation Reactions.

AbstractThis presents a new type of chiral sulfoxide‐phosphine ligands for the asymmetric allylic alkylation (also known as Tsuji‐Trost reaction).

Palladium/sulfoxide-phosphine-catalyzed highly enantioselective allylic etherification and amination.

The Pd/sulfoxide-phosphine-catalyzed highly enantioselective allylic etherification and amination with a wide range of O- and N-nucleophiles have been developed (up to 97% yield, 98.5% ee). The products can also be conveniently transformed into biologically active chiral heterocycles.

Rational design of sulfoxide–phosphine ligands for Pd-catalyzed enantioselective allylic alkylation reactions

A new type of chiral sulfoxide-phosphine ligands have been developed by a rational combination of two privileged scaffolds for Pd-catalyzed asymmetric allylic alkylation reactions. Under optimized conditions, generally high yields (up to 97%) and excellent enantioselectivities (up to >99% ee) were obtained.

ChemInform Abstract: Rh(I)‐Catalyzed Asymmetric Addition of Arylboronic Acids to NH Isatins.

Abstract The transition metal-catalyzed asymmetric variant of the title reaction is normally limited to N-protected isatins. However, Rh(I)/chiral sulfoxide phosphine complexes were found to catalyze the enantioselective addition of arylboronic acids to NH isatins under mild conditions. A variety of chiral 3-aryl-3-hydroxyl-2-oxindoles were obtained with high yields and with good to excellent enantioselectivities (85–92% ee).

Rh(I)-catalyzed asymmetric addition of arylboronic acids to NH isatins

The transition metal-catalyzed asymmetric variant of the title reaction is normally limited to N-protected isatins. However, Rh(I)/chiral sulfoxide phosphine complexes were found to catalyze the enantioselective addition of arylboronic acids to NH isatins under mild conditions. A variety of chiral 3-aryl-3-hydroxyl-2-oxindoles were obtained with high yields and with good to excellent enantioselectivities (85–92% ee).