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Chemical Synthesis

Umicore Precatalysts

Precatalysts for Asymmetric and Cross-Coupling Catalysis

Precatalysts for Asymmetric and Cross-Coupling Catalysis

Introduction
Sigma-Aldrich and Umicore are happy to offer a series of precatalysts for asymmetric catalysis and Pd based cross-coupling catalysis. Our partnership with Umicore allows us to offer a portfolio of metal complexes with batch-to-batch consistency for a plethora of catalytic reactions. Twenty different precatalyst complexes are available, providing access to a hundred different catalytic reactions.

Representative Application
Catalytic hydrogenation is a powerful and effective method used for the reduction of organic molecules. Krische and co-workers have developed methods to utilize this catalytic reaction to generate C–C coupling. After extensive studies done using Rhodium as a precatalyst, Krische and co-workers realized the limitations of Rhodium to catalyze C–C bond forming hydrogenation of only conjugated alkynes. To circumvent these limitations, the utilization of another catalyst was necessary. To expand the scope, Ngai et al. investigated the potency of Ir(COD)2BARF for this transformation. These new complexes proved to be very active with nonconjugated, alkyl-substituted alkynes. In a typical reaction,
Ir(COD)2BARF, DPPF ligand and triphenylacetic acid are used to catalyze the coupling hydrogenation of 3-hexyne with a variety of α-ketoesters to yield α-hydroxyesters in good yields.

Precatalysts Scheme 1

Reference: Ngai, W.-Y. et al. J. Am. Chem. Soc. 2007, 129, 280.

Scheme 1: Iridium catalyzed C–C bond forming hydrogenation


Product Information

Product # Product Name Structure Add to Cart
683353 Bis(2-methylallyl)(1,5-cyclooctadiene)ruthenium(II) Bis(2-methylallyl)(1,5-cyclooctadiene)ruthenium(II)
693774 Bis(cyclooctadiene)iridium(I) tetrakis(3,5-bis(trifluoromethyl)phenyl) Bis(cyclooctadiene)iridium(I) tetrakis(3,5-bis(trifluoromethyl)phenyl)
683086 (Acetylacetonato)(1,5-cyclooctadiene)iridium(I) (Acetylacetonato)(1,5-cyclooctadiene)iridium(I)
683094 Bis(1,5-cyclooctadiene)diiridium(I) dichloride Bis(1,5-cyclooctadiene)diiridium(I) dichloride
683108 (Acetylacetonato)(1,5-cyclooctadiene)rhodium(I) (Acetylacetonato)(1,5-cyclooctadiene)rhodium(I)
683116 (Acetylacetonato)(norbornadiene)rhodium(I) (Acetylacetonato)(norbornadiene)rhodium(I)
683132 Chloro(1,5-cyclooctadiene)rhodium(I) dimer Chloro(1,5-cyclooctadiene)rhodium(I) dimer
683140 Bis(1,5-cyclooctadiene)rhodium(I) tetrafluoroborate Bis(1,5-cyclooctadiene)rhodium(I) tetrafluoroborate
683159 Bis(1,5-cyclooctadiene)rhodium(I) trifluorosulfonate Bis(1,5-cyclooctadiene)rhodium(I) trifluorosulfonate
683167 Bicyclo[2.2.1]hepta-2,5-diene-rhodium(I) chloride dimer Bicyclo[2.2.1]hepta-2,5-diene-rhodium(I) chloride dimer
683175 Bis(norbornadiene)rhodium(I) tetrafluoroborate Bis(norbornadiene)rhodium(I) tetrafluoroborate
686891 Pentamethylcyclopentadienylrhodium(III) chloride dimer Pentamethylcyclopentadienylrhodium(III) chloride dimer
683183 (Acetylacetonato)dicarbonylrhodium(I) (Acetylacetonato)dicarbonylrhodium(I)
683191 Dichloro(1,5-cyclooctadiene)ruthenium(II) polymer Dichloro(1,5-cyclooctadiene)ruthenium(II) polymer
683205 Diiodo(p-cymene)ruthenium(II) dimer Diiodo(<I>p</I>-cymene)ruthenium(II) dimer
683213 Dichloro(p-cymene)ruthenium(II) dimer Dichloro(p-cymene)ruthenium(II) dimer
683221 Benzeneruthenium(II) chloride, dimer Benzeneruthenium(II) chloride, dimer
683396 Allylpalladium(II) chloride dimer Allylpalladium(II) chloride dimer
683388 Palladium(II) acetylacetonate Palladium(II) acetylacetonate
683124 Palladium(II) acetate Pd(OAc)2
683345 Tris(dibenzylideneacetone)dipalladium(0) Pd2dba3

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