Stereocontrolled entry to negamycin from d-glucose
摘要:
Conjugate addition-rearrangement of N-benzylhydroxy-lamine to lactone 6 provides isoxazolidin-5-one 7 which was in turn mesylated at the hydroxy group and subjected to the next skeleton rearrangement to afford 3,5-disubstituted isoxazolidine 10. Standard transformation of 10 gave negamycin lactone 4.
Stereocontrolled entry to negamycin from d-glucose
摘要:
Conjugate addition-rearrangement of N-benzylhydroxy-lamine to lactone 6 provides isoxazolidin-5-one 7 which was in turn mesylated at the hydroxy group and subjected to the next skeleton rearrangement to afford 3,5-disubstituted isoxazolidine 10. Standard transformation of 10 gave negamycin lactone 4.
Conjugate addition-rearrangement of N-benzylhydroxylamine to α,β-unsaturated lactones 1 provides a short and effective route to 3-substituted isoxazolidin-5-ones. High and defined stereochemistry of this reaction with simultaneous liberation of the 5-OH group of the sugar chain, while all other groups remain protected, creates a possibility to switch from sugars of the D-configurational series to