Transition metal catalysis in fluorous media: extension of a new immobilization principle to biphasic and monophasic rhodium-catalyzed hydrosilylations of ketones and enones

Dinh, Long V.; Gladysz, J. A.

doi:10.1016/s0040-4039(99)01924-3

Cited by 56 publications

(29 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As communicated earlier, 1-R f6 and 1-R f8 also afford excellent catalysts for the hydrosilylation of carbonyl compounds, 7 a reaction of considerable importance in fine chemical synthesis. 8 The catalysts were efficiently recycled under fluorous-organic liquid-liquid biphasic conditions.…”

Section: Introductionmentioning

confidence: 69%

See 1 more Smart Citation

Monophasic and biphasic hydrosilylations of enones and ketones using a fluorous rhodium catalyst that is easily recycled under fluorous–organic liquid–liquid biphasic conditions

Dinh

Gladysz

2005

New J. Chem.

Self Cite

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 69%

“…Following our communication, 7 the fluorous rhodium(I) complexes 16 and 17 were employed as catalyst precursors for the hydrosilylation of alkenes. 14 These contain fluorous triarylphosphine ligands and are therefore closer analogs of Wilkinson's catalyst.…”

Section: Discussionmentioning

confidence: 99%

Monophasic and biphasic hydrosilylations of enones and ketones using a fluorous rhodium catalyst that is easily recycled under fluorous–organic liquid–liquid biphasic conditions

Dinh

Gladysz

2005

New J. Chem.

Self Cite

View full text Add to dashboard Cite

“…[6][7][8][9]23] For example, the hydrosilylation of 2-cyclohexenone with dimethylphenylsilane constantly yields 90 % of the desired products over three runs with turnover numbers (TON) of about 110 ( Figure 3). [9] Conversely to these undisputable laboratory-scale advantages, some drawbacks will hinder the industrial utilisation of fluorous catalysis in the near future. The expensive catalyst synthesis on the one hand combined with the ecologically questionable production of fluorinated solvents excludes a usage on a bulk scale.…”

Section: Recovery Strategies For Fluorous Catalystsmentioning

confidence: 99%

Thermoregulated Liquid/Liquid Catalyst Separation and Recycling

2006

View full text Add to dashboard Cite

Considerable effort has been done to overcome the loss of catalyst in homogeneously catalysed processes. In this contribution we describe five recycling concepts for thermoregulated catalyst separation and recycling: fluorous biphasic systems (FBS), thermoregulated phase transfer catalysis (TRPTC), soluble polymer-based catalysis, thermoregulated microemulsions and temperature-dependent multicomponent solvent systems (TMS). Each of these concepts has its own special advantages like low catalyst leaching or simple process engineering but also drawbacks like usage of expensive special solvents or complex and expensive catalysts. In this context, TMS systems exhibit most advantages of the other concepts combined with the possibility to use common and cheap solvents as well as numerous classical molecular catalysts. Therefore, TMS systems are expected to be one of the most promising thermomorphic recycling concepts for industrial scale.

show abstract

“…Ketone hydrosilylation was selected as the test reaction. In previous studies, , the fluorous rhodium(I) complexes ClRh(P(CH 2 CH 2 R f6 ) 3 ) 3 and ClRh(P(CH 2 CH 2 R f8 ) 3 ) 3 ( 1a , b ) had been shown to be effective catalyst precursors under fluorous/organic liquid/liquid biphase conditions (Figure ). These red–orange solids have highly biased fluorous/organic liquid/liquid partition coefficients (99.86:0.14 and 99.88:0.12, CF 3 C 6 F 11 /toluene) commensurate with the high weight percent of fluorine (66.3% and 68.3%).…”

Section: Introductionmentioning

confidence: 95%

Recycling and Delivery of Homogeneous Fluorous Rhodium Catalysts Using Poly(tetrafluoroethylene): “Catalyst-on-a-Tape”

Dinh

Jurisch

Fiedler

et al. 2017

ACS Sustainable Chem. Eng.

Self Cite

View full text Add to dashboard Cite

The red−orange fluorous rhodium(I) complexes ClRh(P((CH 2 ) m R fn ) 3 ) 3 (m/n = 2/6 (1a), 2/8, 3/6, 3/ 10; R fn = (CF 2 ) n−1 CF 3 ) are essentially insoluble in organic solvents at 20 °C but have measurable solubilities in dibutyl ether at 55−65 °C. Under these conditions, they are effective catalyst precursors for the hydrosilylation of cyclohexanone by PhMe 2 SiH. Upon cooling, the catalyst rest states precipitate, giving colorless solutions of C 6 H 11 OSiPhMe 2 . When this sequence is conducted in the presence of poly(tetrafluoroethylene) (PTFE; Teflon) tape, the catalysts precipitate onto the tape but desorb when used in subsequent cycles. The catalyst precursors can also be precoated onto the tape, allowing quantities to be delivered by length instead of mass. Rate measurements (1a) show an induction period in the first cycle, excellent retention of activity in the second and third cycles, and significant activity loss in the fourth. Rhodium leaching is 0.57% and 5.3% for the first two cycles (atomic absorption spectroscopy inductively coupled plasma analysis); (CF 2 ) 5 CF 3 leaching is 11.4% over the first three cycles ( 19 F NMR). Reactions with added mercury show that metallic rhodium is not responsible for catalysis. Identical protocols are applied to 2-octanone, acetophenone, and benzophenone, albeit with some activity loss in the third cycle. Other forms of PTFE can be similarly employed (e.g., Gore-Tex membrane). However, fluorous/organic liquid/ liquid biphase conditions can give better retention of catalyst activity. Nonetheless, the diverse morphologies of PTFE that are commercially available suggest avenues for further optimization.

show abstract

Transition metal catalysis in fluorous media: extension of a new immobilization principle to biphasic and monophasic rhodium-catalyzed hydrosilylations of ketones and enones

Cited by 56 publications

References 20 publications

Monophasic and biphasic hydrosilylations of enones and ketones using a fluorous rhodium catalyst that is easily recycled under fluorous–organic liquid–liquid biphasic conditions

Monophasic and biphasic hydrosilylations of enones and ketones using a fluorous rhodium catalyst that is easily recycled under fluorous–organic liquid–liquid biphasic conditions

Thermoregulated Liquid/Liquid Catalyst Separation and Recycling

Recycling and Delivery of Homogeneous Fluorous Rhodium Catalysts Using Poly(tetrafluoroethylene): “Catalyst-on-a-Tape”

Contact Info

Product

Resources

About