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Title: Asymmetric synthesis of butenolides
Author: Sirit, A.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1994
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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 BF3.Et2O 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.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available