Thiaphosphametallacyclopentadienes as Intermediates in the Cyclotrimerization of Alkynes with their Phosphorus‐Sulfur Analogues

Abstract

Similar intermediates as in the metal catalyzed cyclotrimerization of alkynes can be trapped in the presence of their phosphorus‐sulfur analogues: the metallacyclopentadiene (1) and the bicycle (2) with the partial structure .

Transition metal-mediated cycloaddition reactions of alkynes in organic synthesis

“…129 A decidedly unconventional synthesis of thiophenes from reaction of two alkynes with complexes derived from BrMn(CO)4R2P-(S)H has also been reported. 170 Reactions of (cod)2Ni(0) (cod = 1,5-cyclooctadiene) with alkynes and isocyanates (i.e., heterocumulene analogues of C02; cf. syntheses of maleic anhydride derivatives above) give azametallacycles that upon carbonylation yield maleimide derivatives (eq 82).…”