Synthesis of oxazolidinyl azacycles via ring-closing olefin metathesis: a practical entry to the synthesis of deoxy-azasugars and hydroxypyrrolizidines

Starting with d- and l-serines, an expedient method for the preparation of oxazolidinyl piperidines, azepenes and azacyclooctenes was illustrated as a route to various deoxy-azasugars and hydroxypyrrolizidines. The ring-closing olefin metathesis of oxazolidinyl di-olefins was used as a key-step to construct the azacycles. Consecutive epoxidation, hydrolysis and transannulation of oxazolidinyl azacyclooctene led to hydroxypyrrolizidines.