A new 20-membered macrocyclic dilactam: an unexpected product of a tri-n-butyltin hydride-mediated radical reaction

The tri-n-butyltin hydride-mediated reaction of methyl 3-O-allyl-4,6-di-O-benzyl-2-deoxy-2-(2-iodobenzoylamino)-alpha-D-glucopyranoside affords an unexpected benzomacrodilactam. The structure of this new 20-membered macrocyclic dilactam has been elucidated by electrospray mass and tandem mass spectrometry (ESI-MS/MS) and by H-1, C-13 NMR spectroscopy, COSY, TOCSY, HMQC and HMBC experiments. (C) 2004 Elsevier Ltd. All rights reserved.45163317332