C. Bubert et al. / Tetrahedron Letters 42 (2001) 4037–4039
4039
Ligand 3 was prepared in one-step by the reaction of
References
(1S,2S)-diphenylethylenediamine 7 with benzene-1,2-
disulfonic acid anhydride9 9 as shown in Scheme 2.
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The water-soluble amino sulfonic acid ligands 1, 2 and
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The enantiomerically pure ruthenium catalyst was pre-
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ligand in the presence of base at 40°C. Under standard
conditions,10 acetophenone 10 was converted into
phenethyl alcohol 11 (Scheme 3). The aromatic ketones
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In summary, the preparation of three new water-soluble
ligands has been achieved. Initial experiments demon-
strate that these function are effective chiral ligands in
the reduction of various aromatic ketones under trans-
fer hydrogenation conditions. It is anticipated that
these ligands will enable the development of biphasic
systems and ultimately, supported liquid phase cata-
lysts. Our attention will now turn to this chemistry and
results will be reported in due course.
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Acknowledgements
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We wish to thank AstraZeneca for the funding for this
project through the strategic research fund.
10. For a typical method, see the following paper. Tetra-
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.