E. Thomas, Clare Vickers
May 7, 2009
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Influential Citations
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Journal
Tetrahedron-asymmetry
Abstract
Abstract A stereoselective Mannich reaction between an (S)-tert-butylsulfinimine and methyl (S)-4-benzyloxy-3-methylbutanoate followed by treatment with acid and N-protection was used to prepare methyl (2R,3S)-2-[(S)-2-benzyloxy-1-methylethyl]-3-tert-butoxycarbonylamino-6-methylenedecanoate. This was taken through to methyl (4R,5S)-4-[(S)-2-benzyloxy-1-methylethyl]-5-tert-butoxycarbonylamino-3,8-dioxododecanoate which on treatment with trifluoroacetic acid cyclised stereoselectively to give (1R,2S,4R,5S)-4-[(S)-2-benzyloxy-1-methylethyl]-1-butyl-2-methoxycarbonyl-8-tert-butoxycarbonyl-3-oxo-8-azabicyclo[3.2.1]octane, a potential precursor of stemofoline. Reduction and N-deprotection of this ketone gave (1R,2S,3R,4R,5S)-4-[(S)-2-benzyloxy-1-methylethyl]-1-butyl-2-methoxycarbonyl-8-azabicyclo[3.2.1]octan-3-ol the structure of which was confirmed by X-ray diffraction.