The research on asymmetric organocatalysis has been intensifying since the
beginning of 2000. The growing interest in this research area is driven by the
importance of the chemical synthesis of enantiomerically pure products. While
the general field of asymmetric organocatalysis has been explored intensively, the
recyclability of organocatalysts has not really been considered.
The attachment of phosphonium ion phase tags to chiral binaphthyl-based
phosphoric acid catalyst and the use of these materials in a range of
organocatalytic asymmetric Friedel-Crafts reactions of indoles have been studied.
Placement of tags at the 3 and 3’ positions of the binaphthyl core, so that they
could serve as steric blocking groups, failed to produce an active catalyst.
However, moving the phosphonium ion groups to the 6 and 6’ positions produced
an efficient and enantioselective catalyst. Aided by the presence of the phase tags,
the chiral catalyst was easily recovered at the end of the reactions, and could be
reused several times, albeit with somewhat decreased efficiency and
enantioselectivity.
Furthermore, the synthesis of 1,1’-spirobiindane-7,7’-diol and their
spiroindane-based derivatives have been explored. The (R)-1,1’-spirobiindane-
7,7’-diamine was successfully applied in exo selective asymmetric Diels-Alder
reactions of -unsaturated aldehyde with cyclopentadiene. However, moderate
results aspire further studies in assay of (R)-1,1’-spirobiindane-7,7’-diamine
derivatives, which bear various bulky groups at the 6 and 6’ positions. Moreover,
the conversion of the SPINOL into a spiroindane ketone unfortunately failed,
which was caused by the sterically crowded structure of the SPINOL skeleton. / published_or_final_version / Chemistry / Master / Master of Philosophy
| Identifer | oai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/205871 |
| Date | January 2011 |
| Creators | Hermeke, Julia |
| Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
| Source Sets | Hong Kong University Theses |
| Language | English |
| Detected Language | English |
| Type | PG_Thesis |
| Rights | Creative Commons: Attribution 3.0 Hong Kong License, The author retains all proprietary rights, (such as patent rights) and the right to use in future works. |
| Relation | HKU Theses Online (HKUTO) |
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