Ruthenium-catalyzed oxidative cleavage of olefins to aldehydes.

Three oxidation protocols have been developed to cleave olefins to carbonyl compounds with ruthenium trichloride as catalyst (3.5 mol %). These methods convert olefins that are not fully substituted to aldehydes rather than carboxylic acids. While aryl olefins were cleaved to aromatic aldehydes in excellent yields by using the system of RuCl3-Oxone-NaHCO3 in CH3CN-H2O (1.5:1), aliphatic olefins were converted into alkyl aldehydes with RuCl3-NaIO4 in 1,2-dichloroethane-H2O (1:1) in good to excellent yields. It is noteworthy that terminal aliphatic olefins were cleaved to the corresponding aldehydes in excellent yields by using RuCl3-NaIO4 in CH3CN-H2O (6:1).     

Enantioselective epoxidation of terminal olefins by chiral dioxirane

[see reaction]. This paper describes an enantioselective epoxidation of terminal olefins using chiral ketone 3 as catalyst and Oxone as oxidant. Up to 85% ee has been obtained.     

Catalytic asymmetric allylic and homoallylic diamination of terminal olefins via formal C-H activation

This paper describes a catalytic asymmetric diamination process for terminal olefins at allylic and homoallylic carbons via formal C-H activation using di-tert-butyldiaziridinone as nitrogen source with a catalyst generated from Pd2(dba)3 and chiral phosphorus amidite ligand. A wide variety of readily available terminal olefins can be effectively diaminated in good yields with high regio-, diastereo-, and enantioselectivities.     

Asymmetric olefin aziridination using a newly designed Ru(CO)(salen) complex as the catalyst

Highly enantioselective and good to high-yielding aziridination of conjugated and non-conjugated terminal olefins and cyclic olefins was achieved using a newly designed Ru(CO)(salen) complex as the catalyst in the presence of SESN(3) under mild conditions.     

Palladium(0)-catalyzed addition of CFBr3 to olefins: synthesis of 1,1,3-tribromo-1-fluoroalkanes and 1,2-difluoroalkenes

It has been observed that Pd(0) can be used as a catalyst for the addition of CFBr₃ to olefins to give 1,1,3-tribromo-1-fluoroalkanes with good yields. Both terminal and internal olefins react under these conditions. Treatment of the addition product with zinc and methanol gave 1,2-fluoroalkenes.     

The hydrogenation of olefins using a polymer supported ruthenium complex

RuCl₂(PPH₃)3 has been attached to a phosphinated polymer support (phosphinated polystyrene crosslinked with 2% divinylbenzene) and the reagent converted to the polymer supported analogue of RuClH(PPH₃)₃ in the presence of base. The polymer supported catalyst efficiently hydrogenates terminal olefins under ambient conditions. Hydrogenation of 1-hexene has revealed that the reaction rate is proportional to [Ru], [H₂] and [olefin]/(1 + [olefin]). The polymer support environment allows for selectivity in olefin hydrogenation and under suitable reaction conditions short chain terminal olefins are hydrogenated more rapidly than long chain terminal olefins. The extent of metal loading on the polymer and the reaction solvent composition also influence the reaction selectivity and these effects are discussed.     

One-pot amidation of olefins through Pd-catalyzed coupling of alkylboranes and carbamoyl chlorides

A one-pot synthesis of C1-elongated amides starting from olefins and carbamoyl chlorides has been developed. Alkylboranes, generated by hydroboration of terminal olefins with 9-BBN-H, underwent smooth coupling with carbamoyl chlorides in the presence of palladium catalyst and Cs2CO3.     

Aromatic-amide-derived olefins as a springboard: isomerization-initiated palladium-catalyzed hydrogenation of olefins and reductive decarbonylation of acyl chlorides with hydrosilane

A highly efficient catalytic protocol for the isomerization of substituted amide-derived olefins is presented that successfully uses a hydride palladium catalyst system generated from [PdCl(2)(PPh(3))(2)] and HSi(OEt)(3). The Z to E isomerization was carried out smoothly and resulted in geometrically pure substituted olefins. Apart from the cis-trans isomerization of double bonds, the selective reduction of terminal olefins and activated alkenes was performed with excellent functional group tolerance in the presence of an amide-derived olefin ligand, and the products were obtained in high isolated yields (up to >99?%). Furthermore, the palladium/hydrosilane system was able to promote the reductive decarbonylation of benzoyl chloride when a (Z)-olefin with an aromatic amide moiety was used as a ligand.     

Phosphine‐ and Hydrogen‐Free: Highly Regioselective Ruthenium‐Catalyzed Hydroaminomethylation of Olefins

A highly regioselective ruthenium‐catalyzed hydroaminomethylation of olefins is reported. Using easily available trirutheniumdodecacarbonyl an efficient sequence consisting of a water‐gas shift reaction, hydroformylation of olefins, with subsequent imine or enamine formation and final reduction is realized. This novel procedure is highly practical (ligand‐free, one pot) and economic (low catalyst loading and inexpensive metal). Bulk industrial as well as functionalized olefins react with various amines to give the corresponding tertiary amines generally in high yields (up to 92 %), excellent regioselectivities (n/iso>99:1), and full chemoselectivity in favor of terminal olefins.     

Development of a Ruthenium/Phosphite Catalyst System for Domino Hydroformylation–Reduction of Olefins with Carbon Dioxide

An efficient domino ruthenium‐catalyzed reverse water‐gas‐shift (RWGS)‐hydroformylation‐reduction reaction of olefins to alcohols is reported. Key to success is the use of specific bulky phosphite ligands and triruthenium dodecacarbonyl as the catalyst. Compared to the known ruthenium/chloride system, the new catalyst allows for a more efficient hydrohydroxymethylation of terminal and internal olefins with carbon dioxide at lower temperature. Unwanted hydrogenation of the substrate is prevented. Preliminary mechanism investigations uncovered the homogeneous nature of the active catalyst and the influence of the ligand and additive in individual steps of the reaction sequence.     

Steel-promoted oxidation of olefins in supercritical carbon dioxide using dioxygen in the presence of aldehydes

Oxidation of olefins occurs effectively in supercritical carbon dioxide as the reaction medium with dioxygen as the primary oxidant and aldehydes as sacrificial co-oxidants. No catalyst is required, but the reaction is promoted by the stainless steel of the reactor walls. Depending on the substrate, vinylic oxidation or epoxidation can be the prevailing pathway. Epoxidation is particularly effective for substrates with internal double bonds and for long-chain terminal olefins.     

Synthese und reaktivität von siliciumübergangsmetallkomplexen : X. Übergangsmetall → carbanion-übertragung von fluorsilyleinheiten,ein weg zu fluorsilyl-substituierten phosphor-yliden

The trifluorophosphine complex RhH(PF₃)(PPh₃)₃, the analogue of the well-known homogeneous catalyst RhH(CO)(PPh₃)₃, has been synthesised and found to be a highly active catalyst for both the hydrogenation and isomerisation of terminal olefins, and the complex RhH(PF₃)₂ (PPh₃)₂ has been found to bring about rapid isomerisation of terminal olefins.     

A further breakthrough in biphasic, rhodium-catalyzed hydroformylation: the use of Per(2,6-di-O-methyl)-β-cyclodextrin as inverse phase transfer catalyst

Solvent free biphasic hydroformylalion of various water-insoluble terminal olefins can be achieved in high yields and sclcctivitics by using a water-soluble rhodium/triphenylphosphine trisulfonate catalyst and per(2,6-di-o-mclhyl)-β-cyclodcxtrin as inverse phase transfer catalyst. The catalytic activities were up to ten times higher than those observed without pcr(2,6-di-o-methyl)-β-cyclodextrin.     

Novel palladium(II) complex containing a chelating anionic N-O ligand: efficient carbonylation catalyst

[reaction: see text] A novel palladium(II) complex containing chelating anionic pyridine-2-carboxylato and labile tosylato ligands is a highly efficient catalyst for the carbonylation of organic alcohols and olefins to carboxylic acids/esters. Carbonylation of primary, secondary, and tertiary alcohols as well as linear and functionalized terminal olefins was studied. In all cases remarkable activity and selectivity were observed. The catalyst is stable under reaction conditions even in the absence of excess phosphine ligands.     

Hydroaminomethylation of olefins using a rhodium carbene catalyst

Hydroaminomethylation of terminal as well as internal aliphatic and aromatic olefins with various amines is described in the presence of [Rh(cod)(Imes)Cl] as a catalyst. In general good to excellent yields and high chemoselectivity were obtained in THF at 85-105°C using 0.1 mol% of catalyst.     

Pd(0)/C catalyzed efficient Wacker oxidation of functionalized terminal olefins

Wacker oxidation of terminal olefins was carried out at room temperature and atmospheric pressure by using Pd(0)/C in THF/H₂O (9:1). Palladium(0)/C was proven to be highly efficient catalyst for the Wacker oxidation of terminal olefins to the corresponding methyl ketones. The catalyst was reusable while maintaining its activity and selectivity to a high degree.     

Transition metal–carbene complexes XCVII. π-cyclopentadienyldicarbonylmethylphenylcarbenerhenium

Addition of P(OMe)₃ to [Rh(η³?C₃H₅) (CO)₂] gives [Rh(η³?C₃H₅){P(OMe)₃}₃]; this reacts with hydrogen or silanes to form a species which is an effective hydrogenation catalyst for olefins and a hydrosilylation catalyst for terminal olefins, aldehydes and ketones.     

Cu(I)-catalyzed cycloguanidination of olefins

This paper describes a novel cycloguanidination process using CuCl as catalyst and diaziridinimines as the nitrogen source. A variety of conjugated dienes, trienes, and terminal olefins can be effectively diaminated under mild reaction conditions. For dienes and trienes, the reaction occurs at the terminal double bond with high regioselectivity.     

Palladium chloride and polyethylene glycol promoted oxidation of terminal and internal olefins

Both terminal and internal olefins can he efficiently converted to ketones in polyethylene glycol and water using palladium chloride as the catalyst.     

CuI‐Catalyzed Sequential Diamination and Dehydrogenation of Terminal Olefins: A Facile Approach to Imidazolinones

Diamination of olefins presents a powerful strategy to access vicinal diamines. During the last decade, metal‐catalyzed diamination of olefins has received considerable attention. This study describes an efficient sequential diamination and dehydrogenation process of terminal olefins with CuBr as catalyst and di‐tert‐butyldiaziridinone as nitrogen source, providing a facile and viable approach to a variety of imidazolin‐2‐ones, which are important structural motifs present in various biologically active molecules.