Partial reduction of annulated heterocycles as a general route to medium rings containing oxygen and nitrogen.
The preparation of annulated furans and pyrroles is described as part of a general strategy for the synthesis of medium ring heterocycles. After Birch reduction, the corresponding dihydro compounds were oxidatively cleaved to produce medium ring ethers and amines in an efficient manner. This methodology was successfully applied to the formation of eight- and nine-membered cyclic ethers and nine-membered cyclic amines. Attaching a chiral auxiliary (bismethoxymethylpyrrolidine) to the furan allowed the formation of nine-membered ethers in 95% ee.
Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, U.K. t.j.donahoe@man.ac.uk
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Donohoe
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Raoof
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Linney
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Helliwell
D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D007202:Indicators and Reagents; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D009584:Nitrogen; D010100:Oxygen
D006571:Heterocyclic Compounds; D007202:Indicators and Reagents; D009584:Nitrogen; D010100:Oxygen