Reactions of 1,2-Oxaphospholenes. 7. Anomalous Low Reactivity of a Tertiary Allylic Bromide. The Crystal and Molecular Structure of (E)-4,5-Dibromo-3,5-di-tert-butyl-2-phenyl-1,2-oxaphosphol-3-ene 2-Oxide

Article abstract of DOI:10.1021/jo00040a029

Reaction of 2,2,6,6-tetramethyl-4-heptyn-3-ol (5) with dichlorophenylphosphine leads to (2,2,6,6-tetramethyl-3,4-heptadien-3-yl)phenylphosphinic acid (7), which undergoes Ag⁺-catalyzed cyclization to 3,5-di-tert-butyl-2-phenyl-1,2-oxaphosphol-3