Metallkomplexe funktioneller Isocyanide

Reactions at the coordinated trichloromethyl isocyanide. Part VII. α-Chloroalkenylisocyanide versus oxazolin-2-ylidene(ato) complex formation

“…Strictly aprotic conditions were maintained during work-up which included chromatography on silica and finally led to the a-chloroalkenylisocyanide complexes as microcrystalline yellow (7), orange (8) or light green materials (9) in good yields (Section 3). As indicated by the 1 H and 13 C NMR spectra, complexes 7 and 8 form mixtures of cis(Z)-and trans(E)-isomers which have so far evaded separation.…”

“…To the latter category also belong the reactions with phosphines as nucleophiles which have turned out to be a true bonanza for versatile organometallic/organophosphorus synthons and syntheses such as the combined isocyanoWittig/metallo-nitrile-ylid reagent 2 with its carbonyl-(isocyano)methyleneation and [3+2] cycloaddition reaction patterns [6,8,9]. N C 3 Cl 3 (OC) 5 Cr C 1 1 2…”

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

“…While noncoordinated electron-poor cycloheptatrienes with electron-withdrawing substituents at the end positions of the conjugated system, e.g., 1,6-bis(methoxycarbonyl)cycloheptatriene, do not react with either TCNE or NPTD, they are strongly activated by η 4 -coordination to Fe(CO) 3 . 399 While [1,6- 396 Deprotonation of metal-coordinated C-H acidic isocyanides (CtNCH 2 R with R ) p-tosyl, 405 406,407 Particularly interesting is a comparative study 411 of the reactivity of free, 171, and M(CO) 5 -coordinated (M ) Cr, W), 172, (isocyanomethylene)triphenylphosphorane 410 (cf. Scheme 23).…”

“…Scheme 23). Complexes 172, 411 where the ylidic part is further stabilized through the triphenylphosphino substituent, were the only examples where the 1,3-dipolar metallonitrile ylide could be isolated and characterized. They cycloadd heteroallenes, nitriles, acetylenes, and olefins in [3+2] fashion to give M-Cbonded heterocycles with (e.g.…”

Azide Chemistry – An Inorganic Perspective, Part II[‡][3+2]‐Cycloaddition Reactions of Metal Azides and Related Systems

“…formation of 128) elimination of triphenylphosphine. [569,571] A corresponding chemistry has been established with triphenylboron as substitute for a metal complex fragment; here, both, the adducts with CH-acidic isocyanides (Ph 3 BCNCH 2 CO 2 Et, Ph 3 B-TOSMIC ® ) and the borio nitrile ylides (Li[Ph 3 BCNCHCO 2 Et], Li[Ph 3 BCNCHTos]) could only be generated 'in situ' and were immediately reacted with the respective dipolarophile. [578] As early as 1968, a first triphenylborio nitrile ylide -Li[Ph 3 BCNCPh 2 ] -described as "shortly stable in solution" has been reported by Hesse and coworkers.…”