Vinylidene, acetylide, and carbene complexes from reactions of 2,5-dithiahex-3-yne (MeSC.tplbond.CSMe) with Cp(PMe3)2Ru+

Mechanistic aspects regarding the formation of metal vinylidenes from alkynes and related reactions

“…Often, the backword reaction is also observed (Scheme 1). The most common migrating species is hydrogen, but regarding the alkyne to vinylidene isomerization, migration of SiR 3 [18][19][20][21][22], SnPh 3 [23], SMe [24], and iodine [25] have also been known. The irreversible isomerization of vinylidene ligand in [CpFe(CO) 2 (‚C‚CR 1 R 2 )] + (R 1 , R 2 = Me, Ph) to form the corresponding g 2 -alkyne complex [CpFe(CO) 2 (R 1 C"CR 2 )] + was observed by means of NMR spectroscopy above À50°C, where the higher migrating ability of the Ph than Me group was noted [26].…”

Metal Vinylidenes and Allenylidenes in Catalysis: Applications in Anti‐Markovnikov Additions to Terminal Alkynes and Alkene Metathesis

“…[29,30] Internal alkynes bearing a labile substituent are also prone to form vinylidene derivatives. Trialkylsilyl, [31][32][33][34][35][36][37] alkylthiol, [38] triphenylstannane, [39] and iodide [40,41] are able to migrate and generate functionalized vinylidene metal complexes, and some of them have been involved in catalytic reactions.…”

Facile Formation of a Rhenium Allenylcarbene Complex with an Internal Dithioalkyne

“…In addition, an experimental example of a 1,2-migration of a methylsulfanyl moiety was already observed with Ru II . [20] Within this scheme the barrier for the [2+2] cycloaddition in the bis(alkyne) complex IM1 to yield hypothetical 3a…”