Ferrocenylphosphines bonds

In 1,2-dichloroethane solution the complex displays two subsequent one-electron oxidation steps, reversible in character, that are assigned to dppf/[dppf] ( = -1-0.78 V) and odppf/[odppf] (E° = -f 1.16 V), respectively. In agreement with the strong bonding between the metal and the two ferrocene fragments, the free ferrocenylphosphines are significantly easier to oxidize [ (dppf/[dppf] ) = -i- 0.64 V E° (odppf/[odppf]+) = -1-0.94 V) [187]. 

Recently, a number of ferrocenylphosphines have been developed for asymmetric hydrogenation and C—C bond formation. A breakthrough in the chemistry of ferrocenylphosphines was the optical resolution of ferrocenylamines with tartaric acid [60]. Many optically active ferrocenylphosphines are derived as outlined in Scheme 10.12 [61]. 

The asymmetric cross-coupling was successfully applied to the synthesis of optically active allylsilanes [50,51] (Scheme 10). The reactions of a-(trimethyl-silyl)benzylmagnesium bromide (49) with vinyl bromide (4b), (E)-bromopro-pene (( )-50), and (R)-bromostyrene E)-8) in the presence of 0.5 mol % of a palladium complex coordinated with chiral ferrocenylphosphine, (R)-(S)-PPFA (10a), gave the corresponding (R)-allylsilanes (51) with 95%, 85%, and 95% ee, respectively, which were substituted with phenyl group at the chiral carbon center bonded to the siHcon atom. These allylsilanes were used for the S. ... 

The alkaloid dextromethorphan is an antitussive drug manufactured by Lonza in enantiomerically pure form. While early synthesis involved the tedious resolution of an octahydroi-soquinoline intermediate with mandelic acid, a more recent process takes advantage of the catalytic reduction of a C-N double bond promoted by a chiral Ir/ferrocenylphosphine complex [70]. 

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