Diphosphines - Introduction of Sulfonate Groups by Direct Sulfonation

Diphosphines - Introduction of Sulfonate Groups by Direct Sulfonation 

As already outlined in Section 3.2.1, several water-soluble monophosphines, such as TPPTS, have been synthesized by controlled sulfonation in oleum. In the same way several diphosphines have been sulfonated (Structures 1-5). Although the number of chiral diphosphines reported is ever increasing, the number of sulfonated achiral diphosphines remains limited and includes BINAS-8 (1) [3, 4] and BISBIS (2) [5], both of which contain an aromatic bridge between the two phosphi- 

Aqueous-Phase Organometallic Catalysis, Second Edition 

Copyright 2004 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim 

The diphosphines 1 and 2 were tested as ligands in the rhodium-catalyzed bipha-sic hydroformylation of propene. Both catalysts were found to exhibit higher activities and gave rise to higher l/b ratios [4] than TPPTS. Furthermore, it was shown that displacement of the biphenyl unit of 2 by a binaphthyl unit in 1 leads to an in- 

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