Selective cleavage of N-(2-hydroxyalkyl)amides via oxazolidinone formation: application to chemical degradation of poecillastrin C.

We report herein a mild and selective cleavage of N-(2-hydroxyalkyl)amides based on sequential O-(1-imidazolyl)carboxylation, cyclization to an oxazolidinone, and nucleophilic disconnection. We found that sodium imidazolide enabled temperature-dependent control in the reaction sequence. Application of the method to poecillastrin C at the nmol scale led to successful LC-MS detection of the C39-C54 fragment retaining seven stereogenic centres whose configurations remain unassigned. This fragment will facilitate further studies toward the complete configurational assignment of poecillastrin C.