Borate tetrakis rhodium

Scheme 39.2 Examples of typical rhodium-based catalyst systems and modified derivatives of triphenylphosphine as used to control their solubility with scC02 in homogeneous or multiphase systems (BARF=tetrakis[3,5-bis (trifluoromethyl)phenyl]borate).

B2N4P4Rh2Cii8H,2o, Rhodium(I), tetrakis(l-isocyanobutane)bis[methylenebis(di-phenylphosphine)]di-, bis[tetrapheny 1-borate(l — )], 21 49... 

A complementary, but less pronounced, increase in cis syri) selectivity is provided when diazoacetates with rather small ester groups and rhodium catalysts with bulky ligands, such as iodorhodium(IIl) porphyrins and mcso-tetrakis(2,4,6-triarylbenzoato)di-rhodium(ll) complexes, are employed. For ethyl 2-alkylcyclopropane-l-carboxylates so obtained, a cisfran.s ratio of 2-4 was typical. Notable cis selectivities have also been achieved in the synthesis of ethyl 2-phenylcyclopropane-l-carboxylate with the catalyst [(r/ -C5H5)Fe(CO)2(THF)][BFJ (cis/trans 5.25, see Section 1.2.1.2.4.2.6.3.1.) and copper catalysts prepared in situ from a copper salt [copper(I) iodide, copper(II) acetate or triflate] and sodium tetrakis(7,8,8-trimethyl-4,5,6,7-tetrahydro-2Ff-4,7-methanoindazolyl)borate (3) cis/ trans 2.1-3.2). °... 

BN RhC44HM, Rhodium , tetrakis(l-isocy-anobutane)-, tetraphenylborate(l -), 21 50 BN C Hio, Borate(l -), hydrotris(pyrazolato)-, copper complex, 21 108 BN6Ci5H22, Borate(l -), tris(3,5-dimethylpyr-azolato)hydro-, copper complex, 21 109 BN8Ci2Hi2, Borate(l-), tetrakis(pyrazolato)-, copper complex, 21 110 BjFeN CjoH,, Iron(II), [tris[p.-[(l,2-cy-clohexanedione dioximato)-0 0 ]diphenyl-diborato(2 — )]-NJI JI" X " JI"",... 

B2N4P4Rh2C aH,20, Rhodium(l), tetrakis-(1 -isocyanobutane)bis[methylenebis-(diphenylphosphine)ldi-, bis[tetraphenylborate(l -)], 21 49 BjNACsoHm, Borate(2-), tris[p.-[(l,2-cy-clohexanedione dioximato)-0 O ]diphenyldi-, iron complex, 21 112 B20,Ci4H2g, Boron, bis-p-(2,2-dimethylpropa-noato-0,0 ),-diethyl-p.-oxo-di-, 22 196 B2S3C2H6, [l0B2]-l,2,4,3,5-Trithiadiborolane, 3,5-dimethyl-, 22 225... 

Related Reagents. Bis(bicyclo[2.2.1]hepta-2,5-diene)rho-dium Perchlorate [l,4-Bis(diphenylphosphino)butane](norbora-diene)rhodium Tetrafluroborate Catecholborane (1,5-Cycloocta-diene)[ 1,4-Bis(diphenylphosphino)butane]iridium(I) Tetrafluoro-borate (1,5-Cyclooctadiene)(tricyclohexylphosphine)(pyridine) iridium(I) Hexafluorophosphate Octacarbonyldicobalt Palladium (II) Chloride Tetrakis(triphenylphosphine)palladium(0) 2-Amino-3-picoline Benzylamine. 

One interesting design of macromolecular soluble metal complexes is binding of a rhodium complex with sulfonated triphenylphosphine to a soluble polyelectrolyte, polydiallyldimethylammonium tetrakis(3,5-bis(trifluorome-thyl)phenyl borate. In this ease, the content of phosphine groups enables us to control the catalyst solubility in methanol at high content of the phosphine counter ion, the polymer is insoluble and if the ratio of tetraalkylammonium groups to phosphine groups is 4 1 and 10 1, the polymer is soluble in methanol and is an active catalyst of 1-hexene hydroformylation. The catalyst was separated by ultrafiltration [177]. 

Hayashi and coworkers have developed the highly efficient enantioselective intramolecular [5+2] cycloaddition of heteroatom (O and NTs) alkyne-VCPs 31 under rhodium catalysis [29]. High enantioselectivities of up to >99% ee were achieved for the corresponding cycloadducts 32 by the use of the chiral phosphoramidite ligand 33 in combination with a catalyst such as [RhCKCaH lJi- The reactions were performed at 30 °C in dichloromethane as the solvent and in the presence of sodium tetrakis(3,5-bis(tiilluoromethyl)phe-nyl)borate (Barp) as source of anionic counterion, which produced a series of chiral heteroatom (O and NTs)-tethered cycloadducts in high yields, as shown in Scheme 20.13. 

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