Asymmetric Ruthenium Catalysis Enables Fluorophores with Point Chirality Displaying CPL Properties.

A novel enantiopure π-allylruthenium(IV) precatalyst allowed the enantioselective and stereospecific allylations of indoles and gave access to indolin-3-ones, containing vicinal stereogenic centers. Facile separation of diastereoisomers exhibiting opposite circularly polarized luminescence (CPL) activities in diverse solvents, including water, demonstrated the potential of these sustainable transformations and of the newly prepared molecules.

Modulation of emission properties of phosphine-sulfonate ligand containing copper complexes: playing with solvato-, thermo-, and mechanochromism.

Modulations of various neutral phosphine containing copper(i) complexes exhibiting phosphorescence and TADF are easily achieved by solvent modification restricting intramolecular rotation or by modifying the L-X phosphine-sulfonate chelate. This concept is not limited to solvents as the addition of metallic salts also led to the formation of original well-defined photoluminescent K2CuLX3 and KCuL2X2 cuprate complexes.

Access to 3-Oxindoles from Allylic Alcohols and Indoles.

The site-selective and regioselective allylation of 2-substituted indoles was performed by using a ruthenium(IV) precatalyst containing a phosphine-sulfonate chelate. Mono-, di-, and triallylated indoles were selectively obtained depending on the reaction conditions with the formation of water as the only byproduct. The preparation of 3-oxindole derivatives was then successfully performed owing to air oxidation of the corresponding allylated indoles. Diallylated pseudoindoxyls were proven to be good synthons to perform cyclization through a ring-closing metathesis reaction to afford the corresponding tricyclic adducts. The photophysical properties of the 3-oxindoles were measured, and some of the compounds showed strong fluorescence in water.

Ruthenium Phosphine-Pyridone Catalyzed Cross-Coupling of Alcohols To form α-Alkylated Ketones.

An efficient and green route to access diverse functionalized ketones via dehydrogenative-dehydrative cross-coupling of primary and secondary alcohols is demonstrated. Selective and tunable formation of ketones or alcohols is catalyzed by a recently developed proton responsive ruthenium phosphine-pyridone complex. Light alcohols such as ethanol could be used as alkylating agents in this methodology. Moreover, selective tandem double alkylation of isopropanol is achieved by sequential addition of different alcohols.

Ruthenium catalyzed ß-C(sp3)-H functionalization on the 'privileged' piperazine nucleus.

ß-C(sp3)-H functionalization on the 'privileged' piperazine nucleus has been disclosed using ruthenium catalysis. The ruthenium catalyzed synthesis of a variety of piperazine fused indoles from ortho-piperazinyl (hetero)aryl aldehydes is presented. This transformation takes place via the dehydrogenation of piperazine followed by an intramolecular nucleophilic addition of the transient enamine moiety onto the carbonyl group and aromatization cascade.

Vicinal α,ß-functionalizations of amines: cyclization versus dehydrogenative hydrolysis.

Direct vicinal α,ß-difunctionalization of tertiary cyclic amines is achieved in the presence of ruthenium or iridium transition-metal complexes featuring phosphine-sulfonate chelates. By varying the reaction conditions, α-alkylated lactams were obtained by a formal dehydrogenative hydrolysis in which one molecule of hydrogen is generated from water.

Ruthenium-containing phosphinesulfonate chelate for the hydrogenation of aryl ketones.

Various ruthenium(II) complexes that contain phosphinesulfonate chelate have been synthesized. Arene-free complexes were found to be efficient in the base-free hydrogenation of various aryl ketones, whereas the arene-containing precatalysts required the presence of an amine as an additive. The seminal asymmetric hydrogenation reaction by using the new Sulfo-Binepine ligand was also investigated for the possible intervention of a dihydride species.

Methyl ricinoleate as platform chemical for simultaneous production of fine chemicals and polymer precursors.

The modification of methyl ricinoleate by etherification of the hydroxyl group was accomplished by using a nonclassical ruthenium-catalyzed allylation reaction and also by esterification. Methyl ricinoleate derivatives were engaged in ring-closing metathesis (RCM) reactions leading to biosourced 3,6-dihydropyran and α,ß-unsaturated lactone derivatives with concomitant production of polymer precursors. Sequential RCM/hydrogenation and RCM/cross-metathesis were also implemented as a straightforward method for the synthesis of tetrahydropyran and lactone derivatives as well as valuable monomers (i.e., polyamide precursors).

Transition metal catalyzed nucleophilic allylic substitution: activation of allylic alcohols via π-allylic species.

Modern organic synthesis now requires efficient atom economical synthetic methods operating under greener pathways to achieve C-C and C-heteroatom bond formation. Direct activation of allylic alcohols in the presence of transition metal catalysts leading to electrophilic π-allyl metal intermediates represents such a promising target in the field of nucleophilic allylation reactions. During the last decade, this topic of recognized importance has become an emerging area, and selected transition metals, sometimes associated with alcohol activators, have brought elegant solutions for performing allylic substitution directly from alcohols in a regio, stereo and enantioselective manner.

Regio- and stereoselective syntheses of piperidine derivatives via ruthenium-catalyzed coupling of propargylic amides and allylic alcohols.

Intermolecular selective coupling of linear allylic alcohols and propargylic amides occurs in the presence of a catalytic amount of the cationic ruthenium complex [Cp*Ru(NCCH(3))(3)]PF(6) followed by condensation to generate six-membered cyclic enamides or hemiaminal ethers with water as the only side product.

Isoquinoline derivatives via stepwise regioselective sp(2) and sp(3) C-H bond functionalizations.

Efficient and practically attractive stepwise ruthenium- and palladium-catalyzed regioselective C-H bond functionalizations were achieved to produce 4-substituted tetrahydroisoquinoline derivatives featuring various heteroaromatic substructures in moderate to good yields. Both ruthenium- and palladium-based catalytic processes generated nontoxic and easily separable side products.

Synthesis of azaphilone-based chemical libraries.

The synthesis of azaphilone scaffolds that have been further diversified by cross coupling acylation and amine addition is reported. Methodology development also led to novel modifications including C5 acetoxylation and condensations producing isoquinolin-6(7H) structures. Overall, the library synthesis afforded three azaphilone sublibraries, including vinylogous pyridones which project diversity elements in four sectors of the azaphilone core.

Ruthenium-catalyzed reductive amination of allylic alcohols.

Straighforward access to various saturated amines from allylic alcohols and isostructural mixture can now be achieved in the presence of arene ruthenium catalyst featuring phosphinesulfonate ligand and a hydrogen donor.

sp3 C-H bond activation with ruthenium(II) catalysts and C(3)-alkylation of cyclic amines.

A selective C(3)-alkylation via activation/functionalization of sp(3) C-H bond of saturated cyclic amines was promoted by (arene)ruthenium(II) complexes featuring a bidentate phosphino-sulfonate ligand upon reaction with aldehydes. This highly regioselective sustainable transformation takes place via initial dehydrogenation of cyclic amines and hydrogen autotransfer processes.

Preparation of chiral ruthenium(IV) complexes and applications in regio- and enantioselective allylation of phenols.

Facile preparations of chiral [Ru(Cp*)]- and [Ru(Cp')]-based allyl complexes featuring N,O chelate derived from (+)-nopinone are described. Single crystal X-ray structural analysis of one complex revealed the preferential configuration of the ruthenium centre and the orientation of the unsymmetrical allylic substituent. Applications of these complexes in catalysis for nucleophilic allylic substitution allowed regio- and enantioselective formation of branched allyl ethers from phenols.

Efficient ruthenium-catalyzed synthesis of [3]dendralenes from 1,3-dienic allylic carbonates.

Selective elimination from 1,3-dienic allylic carbonates occurs in the presence of a catalytic amount of [Ru(C(5)Me(5))(4,4'-di-Bu(t)-2,2'-bipyridine)(CH(3)CN)]PF(6) and provides efficient access to a variety of [3]dendralenes.

Ruthenium-catalyzed selective N ,N-diallylation- and N ,N ,O-triallylation of free amino acids.

Selective N ,N-diallylation and N ,N, O-triallylation of free amino acids in the presence of catalytic amounts of RuCp*(MeCN)(3)PF(6) is reported. The crucial influence of the solvent makes these allylation reactions selectively possible.

Highly regio- and stereocontrolled formation of functionalized tricyclo[4.2.1.0(2,8)]non-3-enes.

The electrophilic activations of bicyclo[4.2.1]nonatrienes by 4-isopropyl-1,2,4-triazolinedione, N-iodosuccinimide, or an epoxidation/acidic ring-opening sequence is reported. The subsequent in situ trappings by water, alcohols, or benzoic acids led to original tricyclo[4.2.1.0(2,8)]non-3-enes with high regio- and stereoselectivities. The synthetic potentiality of these synthons is illustrated by the straightforward access to a fused cyclopropane featuring six consecutive controlled stereocenters.