László Kollár

Modern Carbonylation Methods

RECENT ADVANCES IN THE INVESTIGATION OF CARBONYLATION CATALYSTS Kinetics of Carbonylation Reactions Quantum-chemical Studies on the Mechanism of Transition Metal Catalysed Cabonylation Chelating Ligands with Various Bite-angles in Carbonylation Reactions (Electronic and Steric Effects of Ligands in Carbonylation Reactions) Reactivity of Pincer Complexes Towards Carbon Monoxide The Use of Heterobimetallic Systems in Carbonylations Homogenization of Heterogeneous Carbonylation Catalysts Novel Chiral Ligands Designed for Enantioselective Hydroformylation METHODOLOGICAL DEVELOPMENTS IN CARBONYLATION REACTIONS Enantioselective Carbonylation Reactions Asymmetric Cyclocarbonylations Microwave-promoted Cabonylations Recent Advances in Two-phase Carbonylation Ionic Liquids in Carbonylation Reactions Industrial Applications of Transition Metal Catalysed Carbonylation Reactions SYNTHETIC APPLICATION OF TRANSITION METAL CATALYSED CARBONYLATION REACTIONS Carbonylative Ring Expansion Reactions Carbonylation of Allenes Carbonylation of Oxiranes Homogeneous Carbonylation Reactions in the Synthesis of Compounds of Pharmaceutical Importance The Synthesis of O-, N- and S-containing Heterocycles in Homogeneous Carbonylation Reactions Pd-assisted Synthesis of Heterocycles via Carbonylation Reactions

P-heterocycles as ligands in homogeneous catalytic reactions.

Ligands with phosphorus donor atoms have probably been the most studied ones in transition metal catalyzed reactions. Because of the recognition of the carbon-metal bonding properties and the mechanistic understanding of the basic catalytic reactions, the application of homogeneous catalytic reactions is steadily emerging. The definition of the scope and limitations has rendered many of the transition metalphosphorus ligand catalytic systems the most efficient solution to practical problems. Most of the “textbook” homogeneous catalytic reactions, among them enantioselective reactions, apply tertiary phosphines as most conventional ligands. Among the ligands with phosphorus of sp3 hybridization, the cyclic ligands have reached an impressive maturity. In spite of this fact, in general, the chemistry of phosphorus heterocycles is much less developed than the analogous nitrogen chemistry. It is especially true in the area of coordination chemistry, even though cyclic phosphines proved to be excellent ligands for catalysis.1-5 Thus, the main objective of this review is to shed some more light into the synthesis, coordination chemistry, and catalysis of some 3-, 4-, 5-, 6-, and 7-membered Pheterocycles of unprecedented structure not reviewed before. The objective of this paper is not to present a full coVerage of P(III) deriVatiVes, since several aspects of these types of P-heterocycles such as theoretical background, synthesis, * To whom correspondence should be addressed. E-mail: kollar@ttk.pte.hu. † This paper is dedicated to the memory of Professor Pascal Le Floch. György Keglevich was born in Budapest, Hungary, in 1957. He received his M.Sc. under the supervision of Professors L. Tõke and Imre Petneházy from the Technical University of Budapest in 1981. After getting the Ph.D., he was a postdoctoral fellow with Professor L. D. Quin (at Duke University, Durham, NC). In 1994, he received his D.Sc. from the Hungarian Academy of Sciences. After different teaching positions, he was appointed full professor at the Department of Organic Chemical Technology, Budapest University of Technology and Economics, in 1996, and he was the head of this Department in the period of 1999-2006. After a fusion in 2007, he has been the head of the Department of Organic Chemistry and Technology. His research interests include organophosphorus and environmentally friendly chemistry comprising P-heterocycles, low-coordinated P-fragments, P(III)-ligands, their boraneand transition metal complexes, catalytic reactions, selective syntheses, resolution of P(IV) compounds, microwave synthesis, ionic liquids, and optimization of reactions by on-line methods. Chem. Rev. 2010, 110, 4257–4302 4257

NMR investigation of Pd(II)-Pd(0) reduction in the presence of mono- and ditertiary phosphines

The reduction of Pd(II) to Pd(0) was investigated in the presence of both monodentate (PPh3) and bidentate (dppp=1,3-bis(diphenylphosphino)propane) phosphines. It was shown by 31P NMR measurements that triphenylphosphine can reduce Pd(OAc)2 to zerovalent palladium in toluene and dppp is mainly responsible for the reduction in dmf resulting in dppp hemioxide and dppp dioxide. Both mono- and bidentate coordinations of dppp in intermediate species are proposed on the basis of in situ NMR studies. In the presence of two equivalents of silver triflate, the formation of the [Pd(dppp)(PPh3)2]2+ square-planar complex cation has been observed without any reduction of Pd(II) to Pd(0) species.

Temperature dependence of the asymmetric induction in the PtCl(SnCl3)[(−)-(2S,4S)-2,4-bis(diphenylphosphino)pentane]-catalyzed enantioselective hydroformylation reaction

Abstract Asymmetric hydroformylation of some prochiral olefins has been shown to be catalyzed by a new (preformed) PtCl(SnCl 3 )[( S , S )-BDPP] (( S , S )-BDPP = (−)-(2 S ,4 S )-2,4-bis(diphenylphosphino)pentane) catalyst. Vinylidene carboxylic esters are hydroformylated regioselectively but with rather moderate enantioselectivity. In hydroformylation of styrene the linear non chiral regioisomer 3-phenylpropanal is the main product, but the enantioselective formation of 2-phenylpropanal is strongly influenced by the reaction temperature, The S -enantiomer predominate at lower and the R -species at higher temperatures. Appropriate choices of the partial pressure of CO and H 2 led to a relatively high (76.5%) enantiomeric excess.

Asymmetric hydroformylation of unsaturated esters with PtCl(SnCl3)[(R,R)-Diop] catalyst

Dimethyl 2-(formylmethyl)butanedioate (2e) has been synthesized regioselectively with an enantiomeric excess of more than 82% by the homogeneous catalytic hydroformylation of dimethyl itaconate (1e) with PtCl(SnCl3)[(R,R)-DIOP] as the catalyst precursor. Under the conditions used a competitive hydrogenation to dimethyl 2-methylsuccinate (3e) takes place. This reaction occurs with an optical yield of up to 51%. For other vinylidene esters 1 the asymmetric induction was lower both in the hydroformylation and in the competitive hydrogenation. The relationship between the absolute configuration of the predominant antipodes and the possible transition states responsible for the enantioface discrimination is discussed in terms of a model developed and successfully used for olefinic hydrocarbons as substrates.

Asymmetric hydroformylation with Pt-phosphine-SnCl2 and Pt-bisphosphine-CuCl2 (or CuCl) catalytic systems

Abstract A study has been made of asymmetric hydroformylation of styrene with PtCl 2 (PPh 3 ) 2 + bisphosphine + SnCl 2 (bisphosphine: BDPP = (−)-(2 S ,4 S )-2,4-bis(diphenylphosphino)pentane or DIOP = (−)-(4 R ,5 R )-2,2-dimethyl-4,5-bis(diphenylphosphinomethyl)-1,3-dioxolane) and PtCl 2 (bisphosphine) + PPh 3 + SnCl 2 catalysts prepared “in situ”. The presence of an excess of the phosphine ligand slightly lowered the reaction rate, but the enantioselectivity of these systems is significantly higher than those involving PtCl(SnCl 3 )(bisphosphine) catalysts. Under mild reaction conditions 88.8% enantiomeric excess was achieved. Replacing SnCl 2 in these catalysts by CuCl 2 or CuCl gave a new homogeneous catalytic system which is active at higher reaction temperature (> 100°C), but has a rather moderate enantioselectivity.

Asymmetric hydroformylation of styrene catalysed by platinum-tin complexes with chiral bis-binaphthophosphole ligands

Abstract A set of novel bidentate ligands 2 , 3 and 4 , which have two axially chiral binaphthophospholyl (BNP) substituents connected through a carbon chain of different lengths (two to four atoms), has been synthesised by alkylating the binaphthophospholyl anion with the appropriate diiodide or ditosylate. In solution the free diphospholes display fluxional behaviour because of the ready atropisomerisation of the binaphthyl backbone. Consistent with their structure, the reaction of the bis(BNP) compounds with platinum(II) derivatives gives either cis chelate mononuclear complexes or trans phosphorus-bridged polynuclear derivatives. The latter can be converted into the mononuclear species by warming them in the presence of SnCl 2 . Coordination to platinum enhances the conformational stability of 3 and 4 and separate diastereomeric complexes can be detected in solution up to about 50°C. In the presence of SnCl 2 , the platinum complexes containing 3 and 4 give rise to catalysts which exhibit remarkable activity in the hydroformylation of styrene. Under optimum conditions, reaction takes place with unprecedently high branched selectivity (80%-5%) and moderate enantioselectivity (up to 45% e.e.).

Phosphinerhodium complexes as homogeneous catalysts

Abstract The enantioselectivity of catalysts obtained in situ from [Rh(nbd)Cl] 2 , (+)-DIOP and triethyl amine for the hydrogenation of aryl ketones is significantly increased if benzene is used as a solvent. Optical yields of 55–84% were achieved at 50° C and 70 bar H 2 .

Temperature dependence of the enantioselective hydroformylation with PtCl2[(S)-BINAP] + SnCl2 catalyst and the dynamic NMR study of the catalytic precursor

Abstract The strong temperature dependence of the absolute configuration of the α-phenylpropanal formed in the PtCl2[(S)-BINAP]-catalysed hydroformylation (BINAP=2,2′-bis(diphenylphosphino)-1,1′-binaphthyl) of styrene is explained by the restricted rotation of the phenyl rings on the basis of a dynamic NMR study.

Platinum-catalysed enantioselective hydroformylation of styrene. Platinum-diphosphine-tin(II) fluoride catalytic system: a novel asymmetric hydroformylation catalyst

Abstract Enantioselective hydroformylation of styrene was carried out in the presence of platinum-containing catalysts. Tin(II) fluoride was used as cocatalyst, giving a catalytic system of unusually high stability. When the optically active diphosphine 2,4-bis(diphenylphosphino)pentane (BDPP) was used the absolute configuration of the 2-phenylpropanal formed varied with the temperature used. In dichloromethane the enantiomeric excess depends strongly on the temperature used. Although the addition of 2-diphenylphosphino-pyridine to the catalytic system strongly reduces the catalytic activity, the BDPP-2-diphenylphosphino-pyridine “mixed-phosphine system” gave 86.7% e.e.