Rational design, synthesis, and reactivity of lactendiynes, a new class of cyclic enediynes ortho-fused with the b-lactam ring

A series of 10-membered cyclic enediynes trans-fused with N-protected and N-unprotected β-lactams have been stereoselectively prepared. These compounds were found to be stable toward Bergman cycloaramatization, which, an the other hand, takes place readily when the azetidinone ring is opened.