Ethylidenphosphoran‐Ethenylfluorphosphoran‐(λ 5 σ 4 P‐λ 5 σ 5 P)‐Umlagerung

Ethylidenephosphorane – Ethenylfluorophosphorane (2λ 5 σ 4 P–λ 5 σ 5 P) Rearrangement 2‐Methoxy‐1,3,2‐dioxaphospholane ( 4 ) reacts with 2,2,4,4‐tetrakis(trifluoromethyl)‐1,3‐dithietane ( 1 ) to furnish 2‐methoxy‐2‐[2,2,2,‐trifluoro‐1‐(trifluoromethyl)ethylidene]‐1,3,2λ 5 σ 5 ‐dioxaphospholane ( 6 ) which rearranges upon standing at ambient temperature to form 2‐[2,2‐difluoro‐1‐(trifluoromethyl)ethenyl]‐2‐fluoro‐2‐methoxy‐1,3,2λ 5 σ 5 ‐dioxaphospholane ( 7 ).