An electrochemical approach has previously been described for the selenenylation-deselenenylation of alkenes using diphenyl diselenide. The use of electrochemistry enabled diphenyl diselenide to be used in catalytic amounts to convert alkenes into allylic ethers. i 10 mol% (PhSe)2 Electrolysis OMe The electrochemical use of diselenides bearing a chiral side chain has now been investigated. The initial investigations involved the use of diphenyl diselenide, in conditions which varied considerably from those described previously in the literature. By using just 10 mol% diphenyl diselenide, the conversion of alkene A into allylic ether B was achieved in 91% yield. OMe PhAArn, 10 mol% (ArSe)2 Ar=Ph 91% yield Ph CO<sub>2</sub>Me - Ph C02Me Ar=Chiral 55% yield Electrolysis A B Having established viable conditions using diphenyl diselenide, a range of chiral non-racemic diselenides was now used for the same conversion. Mixed results were obtained, with yields of B ranging from 19% to 55% and selectivities ranging from 0% to 69% ee. The reaction of several chiral diselenides was investigated in depth and a likely mechanism for the addition elimination sequence proposed. The investigation was widened to include more alkenes and different reaction conditions, though no alkenes proved as ideal a substrate as A. In an attempt to improve the efficiency of these electrochemical reactions, the synthesis of novel diselenides incorporating new design principles was undertaken, resulting in the synthesis of diselenide C which provided the highest selectivity in the electrochemical reaction.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:583395 |
| Date | January 2004 |
| Creators | Cox, Matthew |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/54544/ |
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