Synthesis and Structure of Functionalized Cyclododecadiynes and ‐dienes

The cyclododecadiynes 3b–d, 8b–d , and 10b–c with functionalities in two propargylic positions, as well as the monofunctionalized diyne 13b have been prepared from simple open‐chain building blocks. In the DMPU ( = N , N '‐dimethylpropyleneurea)‐assisted ring‐closing alkylation of 1,7‐diynes, the twelve‐membered ring compounds have been prepared in yields of 16–55%. The preparation of the diene‐diyne 15 and the cyclododeca‐5,11‐diyne‐1,4‐dione 18 are described.