Hydride intermediates in homogeneous hydrogenation reactions of olefins and acetylenes using rhodium catalysts

Young, J. F.; Osborn, John A.; Jardine, F. H.; Wilkinson, Geoffrey

doi:10.1039/c19650000131

Cited by 173 publications

(183 citation statements)

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“…One of the most active of these complexes, which has been developed for the hydrogenation of alkenes at ambient temperatures and pressures, is that of Wilkinson and coworkers (22), namely, chlorotris(triphenylphosphine)rhodium(I) [Rh(PPh3)3CI]. The chemistry of the hydrogenation process has been described in detail for this and related catalysts (18).…”

Section: Discussionmentioning

confidence: 99%

A method for the modulation of membrane fluidity: homogeneous catalytic hydrogenation of phospholipids and phospholipids and phospholipid-water model biomembranes.

Chapman¹,

Quinn²

1976

Proc. Natl. Acad. Sci. U.S.A.

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The fatty acids associated with the phospholipids of cell membranes, and particularly their degree of unsaturation, contribute to the fluidity of their structure and hence determine many of their biological properties. We Many cell membranes have their lipid component in the fluid state, that is, the lipids are above their main endothermic transition temperature (5-7), but some cell membranes consist of lipids in both rigid and fluid conditions (8, 9). The relationship between membrane lipid fluidity and biochemical and biological processes has been actively studied (10, 11). Membrane-bound enzyme activities, transport processes, malignant transformation, membrane adhesion and membrane fusion, protein rotation and diffusion, and patch and cap formation have all been related to membrane lipid fluidity (see ref. 12 for review). The idea that some biological systems, e.g., thermophilic microorganisms, have a feedback mechanism designed to maintain membrane fluidity constant by changing the length or degree of unsaturation of the associated fatty acids (13) has been supported by several experiments (11,14).Because of this link between membrane lipid fluidity and various cellular processes, several experimental techniques have been devised to alter the lipid fluidity of cell membranes, including genetic, nutritional, and temperature manipulation (15,16). In the present paper we explore a new approach to this idea of modulating membrane lipid and membrane fluidity. This is the technique of catalytic hydrogenation. The catalytic hydrogenation of unsaturated triglycerides is a well-known process, particularly used for the production of hardened fats, and has considerable and well-known commercial exploitation. All natural oils (glycerides) contain a spectrum of fatty acids containing different numbers of double bonds (analogous to the fatty acids of the phospholipid constituents of cell membranes). Studies of the heterogeneous catalytic hydrogenation of glycerides show that the fatty acyl residues with one double bond are hydrogenated more slowly or at a later stage than those with two or more double bonds, also that the hydrogenation of a polyunsaturated acyl residue, once started, tends to stop or slow down considerably at the monoenoic stage (17). It is clear that if the controlled catalytic hydrogenation of the unsaturated fatty acid residues of the phospholipids within cell membrane structures could be accomplished, it would lead to a highly selective method of controlling membrane fluidity as well as providing a critical examination of the functional role for the particular unsaturated fatty acids present, e.g., the polyunsaturated fatty acids such as linoleic and linolenic acids found abundantly in some cell membranes.In this paper we report our studies with two catalytic processes for hydrogenation, namely, heterogeneous and homogeneous catalysis. Phospholipids containing unsaturated fatty acyl constituents have been hydrogenated in organic solvents in order to compare the two processes. Phospholipids ...

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Section: Discussionmentioning

confidence: 99%

A method for the modulation of membrane fluidity: homogeneous catalytic hydrogenation of phospholipids and phospholipids and phospholipid-water model biomembranes.

Chapman¹,

Quinn²

1976

Proc. Natl. Acad. Sci. U.S.A.

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“…Roughly at the same time as Chart's discovery, Wilkinson's hydrogénation catalyst was reported (9). The mechanism of the catalytic cycle, which alternates between Rh(I) and Rh(III) intermediates, explicitly involves both H 2 addition and what is regarded (at least in today's language) as a reductive elimination of a C-H bond.…”

Section: + H 2 -» M(h 2 ) M(h) 2 (4)mentioning

confidence: 99%

Organometallic C—H Bond Activation: An Introduction

Goldman¹,

Goldberg²

2004

ACS Symposium Series

113

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An introduction to the field of activation and fimctionalization of C-H bonds by solution-phase transition -metal-based systems is presented, with an emphasis on the activation of aliphatic C-H bonds. The focus of this chapter is on stoichiometric and catalytic reactions that operate via organometallic mechanisms, i.e., those in which a bond is formed between the metal center and the carbon undergoing reactionThe carbon-hydrogen bond is the un-functional group. Its unique position in organic chemistry is well illustrated by the standard representation of organic molecules: the presence of C-H bonds is indicated simply by the absence of any other bond. This "invisibility" of C-H bonds reflects both their ubiquitous nature and their lack of reactivity. With these characteristics in mind it is clear that if the ability to selectively fiinctionalize C-H bonds were well developed, it could potentially constitute the most broadly applicable and powerful class of transformations in organic synthesis. Realization of such potential could revolutionize the synthesis of organic molecules ranging in complexity from methanol to the most elaborate natural or unnatural products.The following chapters in this volume offer a view of many of the current leading research efforts in this field, in particular those focused on the activation

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“…The combined organic phase was dried over MgSO 4 , filtered and the solvent was removed. The crude product was purified by chromatography on silica gel using methanol-CH 2 (0.252 g, 0.54 mmol) in the same way as described above for 5. The crude product was purified by PLC on silica gel using methanol-CH 2 Cl 2 (1:30) as an eluent to give (R,R)-6 (0.239 g, 89%) as a white solid.…”

Section: Methodsmentioning

confidence: 99%

“…Trivalent phosphane compounds have gained great attention in organic chemistry since 1948 [1][2][3][4][5][6][7][8] due to their complexing ability and their potential use as catalysts in homogenous reactions, such as hydrogenation 9,10 for example. Although P-heterocyclic ligands are becoming the subjects of a more and more important research area, However, with most of these reported methods the phosphane is difficult to purify.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of achiral and new chiral crown ethers containing a triphenylphosphane unit

Szabó¹,

Petri²,

Gergely³

et al. 2015

Arkivoc

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Synthesis and characterization of achiral 1 and new chiral macrocycles (R,R)-2, (S,S)-3 and (S,S)-4 containing a triphenylphosphanone unit have been accomplished. A new method was used for the reduction of phosphanones to phosphanes. Using this method new potential catalyst ligands 15, (R,R)-16, (S,S)-17 and (S,S)-18 containing a triphenylphosphane unit were synthesized and characterized. These ligands are promising candidates for coordination chemistry studies and homogeneous catalytic reactions.

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Hydride intermediates in homogeneous hydrogenation reactions of olefins and acetylenes using rhodium catalysts

Cited by 173 publications

References 0 publications

A method for the modulation of membrane fluidity: homogeneous catalytic hydrogenation of phospholipids and phospholipids and phospholipid-water model biomembranes.

A method for the modulation of membrane fluidity: homogeneous catalytic hydrogenation of phospholipids and phospholipids and phospholipid-water model biomembranes.

Organometallic C—H Bond Activation: An Introduction

Synthesis of achiral and new chiral crown ethers containing a triphenylphosphane unit

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