Synthesis of 3-oxooxa- and 3-oxoazacycloalk-4-enes by ring-closing metathesis. Application to the synthesis of an inhibitor of cathepsin K

3-Oxooxa- and 3-oxoazacycloalk-4-enes were obtained with good yield from 1-(ω-alkenyloxy)- and 1-(ω-alkenylamino)-but-3-en-2-ones by using a ring-closing metathesis. This methodology has been used to synthesize an inhibitor of cathepsin K.