Blocking Intramolecular Cycloadditions between C≡C Triple Bonds and Electrophilic Phosphinidene Complexes: Generation of Intermediates Able To React with Arenes

Electrophilic terminal phosphinidene complexes [R1P-W(CO)5] bearing 2-alkynylphenyl R1 substituents undergo a spontaneous cyclization to give intermediate five-membered species which are able to perform an electrophilic substitution reaction with toluene and mesitylene. An intramolecular version of this reaction is possible with appropriate R substituents on the C≡C triple bond.