Optically active butenolides have been prepared from the reaction of chiral 1,3-dioxolans and 1,3-oxazolidines with the silyl enol ethers 2-trimethylsilyloxyfuran and 2-trimethylsilyoxy-4-methoxyfuran. Chiral 1,3-dioxolans were prepared in high yields (80-96%) by the exchange reaction of diisopropyl L-tartrate with triethyl orthoformate, triethyl orthoacetate and triethyl orthobenzoate. These were reacted with 2-trimethylsilyoxyfuran (TMSOF) under Lewis acid conditions to give optically active butenolides. The stereoselectivity and yield were not very good. (-)-(R)-Phenyl glycinol and (-)-(1R,2R)-norpseudoephedrine, as their N-tosyl derivatives were reacted with trimethyl orthobenzoate to furnish the chiral 1,3-oxazolidines in high yields (79-85%). Their reaction with TMSOF and 2-trimethylsilyoxy-4-methoxyfuran in the presence of BF<SUB>3</SUB>.Et<SUB>2</SUB>O afforded the optically active butenolides. Moderate yield, but high stereoselectivity, were obtained. Conjugate addition of lithium organocuprates and sulphur stabilized carbanions to the chiral butenolides gave γ-lactones with high stereoselectivity.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:639047 |
| Date | January 1994 |
| Creators | Sirit, A. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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