Herein, we describe unprecedented access to all-carbon or heterocyclic seven-membered ring frameworks from 1,8-ene-ynes promoted by inexpensive low-valent titanium(ii) species, readily available from a combination of Ti(OiPr)4 and Grignard reagent.
Low-valent dialkoxytitanium(ii): a useful tool for the synthesis of functionalized seven-membered ring compounds
