Synthesis of Annelated Phospholes through Intramolecular CH Activation by Monovalent Phosphorus

Abstract

Electrophilic terminal phosphinidene complexes [Ar-Ar-P-W(CO)5 ] (Ar-Ar: biaryl or an analogue thereof) undergo a spontaneous insertion of the phosphorus atom into the vicinal CH bonds to give annelated phospholes. Twelve examples are described, including biphenyl, thienyl, pyrrolyl, and benzofuryl groups as biaryl moieties. The activation energy of the insertion reaction is quite low (about 2 kcal mol(-1) ).

Transition‐Metal‐Like Reversible Cycloadditions of [tBuSP‐W(CO)5] with Alkenes and Alkynes

“…Reversible coordination of low‐valent transition‐metal complexes to alkenes and alkynes is a key step in many catalytic transformations . Phosphinidenes have been proved to display somewhat transition‐metal‐like behavior, such as oxidative addition, reductive elimination, and ligand exchange . To our delight, the tert ‐butylthiophosphinidene complex [ t BuSP‐W(CO) 5 ], which is stabilized by sulfur and coordinated by W(CO) 5 , undergoes facile and reversible cycloadditions with alkenes and alkynes (Scheme ).…”

Activation of A–H bonds (A = B, C, N, O, Si) by using monovalent phosphorus complexes [RP→M]

“…Very recently, we have been able to take advantage of this proximity effect to devise a new synthesis of annelated phospholes [24] (Scheme 9). This approach can be easily generalized.…”

Recent studies of the synthesis, functionalization, optoelectronic properties and applications of dibenzophospholes

“…The nal step involved removal of the W(CO) 5 tungsten moiety by heating with 1,1 0 -(1,2-ethanediyl)bis(1,1-diphenyl)phosphine in reuxing xylene to give 5-phenyldibenzophosphole 1 in 25% yield (Scheme 69). 47 3.1.8. P-Quaternisation.…”