Double Stabilization of Highly Strained Six-Membered Rings by Phosphonium and Transition Metal

Cycloalkynes and cyclocumulenes have attracted considerable attention because they are key intermediates in or- ganic synthesis. Stabilization of these highly active species remains a challenge for synthetic chemists. Recently, we found that phosphonium and transition metal replacement can double stabilize these species. Using this strategy, a series of highly strained six-membered rings with remarkable stability have been synthesized. Herein, the latest progress of our group is re-