Isolation of a C3-metalated indolizine complex and a phosphonium ring-fused bicyclic metallafuran from the osmium-induced transformation of pyridine-tethered alkynes. (13th September 2019)

• Record Type: Journal Article
• Authors: Chung, Lai-Hon; Yeung, Chi-Fung; Shek, Hau-Lam; Wong, Chun-Yuen
• Is Part Of: Faraday discussions. Volume 220(2020)
• Page Start: 196
• Page End: 207
• Publication Date: 2019-09-13
• Subjects: Chemistry -- Periodicals; Metallurgy -- Periodicals; Electrochemistry -- Periodicals; 540
• DOI: 10.1039/c9fd00048h
• Languages: English
• ISSNs: 1359-6640

Abstract

Abstract : Isolation of the C3-metalated indolizine and bicyclic osmafuran complexes revealed the intermediacy of metal–vinylidene species regarding [Os(dppm)2 Cl] + -mediated alkyne transformations. Abstract : The first C3-metalated indolizine complex was prepared from the reaction between cis -[Os(dppm)2 Cl2 ] (dppm = 1, 1-bis(diphenylphosphino)methane) and propargylic pyridine, HCCC(OH)(2-py)2 . A phosphonium ring-fused bicyclic osmafuran complex was also prepared from the reaction between cis -[Os(dppm)2 Cl2 ] and pyridyl ynone, HCC(CO)(2-py). The formation of these two products revealed the intermediacy of metal–vinylidene species regarding [Os(dppm)2 Cl] + -mediated alkyne transformations. Comparison of the d 6 transition-metal precursors employed to activate HCCC(OH)(2-py)2 suggests that precursors with higher π-basicity favor the vinylidene-involving pathway.