Chemie der Isoblausäure, 9. Dreikomponenten‐Cycloadditionen mit Cyanokomplexen

Abstract

~~~~~ Chemistry of Hydrogen Isocyanide. 9A novel and obviously general reaction of the coordinated cyano ligand in [M(CN)(CO),]-(M = Cr, W) is reported, viz. its high-yield one-step [2 + 1 + 21 cycloaddition with a great variety of isocyanides and ketones resulting in carbenoid metal complexes of five-membered N,O heterocycles. The structure of the product l a from [W(CN)(CO),]-, tert-butyl isocyanide, and diethyl ketone has been elucidated by X-ray diffraction and found to contain a C-bound non-aromatic 4-aminooxazoline with an unprecedented x-delocalization along the -Three-Component Cycloadditions with Cyan0 Complexeschain which is also evident from severe low-field shifts of the C-2 and C-4 signals in the 13C-NMR spectra. The heterocycles are cleaved off the metal by oxidative decomposition with KMn04/Fe(N0& to give the corresponding oxazolinones, e.g. 4, with a high potential for biological activity. The general validity of this reactivity pattern for metal cyanides is further demonstrated by the successful incorporation of cyanoiron(I1) and -cobalt(III) species in these three-component cycloaddition reactions.Im Gegensatz zur omnipotenten metallorganischen Chemie des Kohlenmonoxids ist die des isoelektronischen CNvollig unterentwickelt. Am besten illustrieren dies die wenig prazisen Vorstellungen, die man bis heute uber den Mechanismus selbst eines so wichtigen, im Zigtausend-Tonnenmal3stab durchgefuhrten Prozesses wie der (Butadien-)-Hydrocyanierung -Du Ponts AdiponitrilprozeD -hat [']. Dabei bringt Cyanid als hervorragender Ligand und gut verfugbares C1-und N1-Synthon alle Voraussetzungen fur eine metallorganische Schlusselsubstanz rnit [31.In den letzten Jahren konnten wir der einzigen klassischen Reaktion des Cyanoliganden, der ionischen N-Alkylierung, einige weitere an die Seite stellen, so eine ,,radikalische Alkylierung" wie diverse Hydroisocyanierungen von Mehrfachbindungssystemen und kleinen Ringen, an die sich hlu- fig Ergebnisse und DiskussionAquimolare Mengen an Pentacarbonyl(isob1ausaure)wolfram und Cyclohexylisocyanid reagieren in Aceton mit guter [*I Neue Adresse: Deutsches Museum, Museumsinsel 1, D-80538Miinchen.

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

“…In a three-component [2+2+1] reaction (eq 134) of a range of cyano complexes L n M(CN) [L n M = Cr(CO) 5 , Mo(CO) 5 , W(CO) 5 , Mn 2 (CO) 9 , (Cp)(CO)Fe(CN), (Cp)(dppe)Fe] with a wide variety of different ketones and isocyanides, carbenoid oxazoline complexes 506 are formed, which by oxidative degradation give attractive yields of 4-amino- and 4-iminooxazolidin-2-ones. −

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2-Amino-2-oxazoline and trialkylisourea Pt(ii) complexes derived from organocyanamides

“…[23][24][25][26][27] Complexes with amino-functionalized oxazolines have been derived from a three-component cycloaddition of an isocyanide (CNR 1 ) and a ketone (R 2 R 3 C᎐ ᎐ O) to ligated hydrogen isocyanide (M-CNH) to form a carbenoid C2-metal coordinated 4-amino-oxazoline (b) in various transition metal complexes [M{CNC(NHR 1 )C(R 2 )(R 3 )O}]. [28][29][30][31][32] In spite of the interest of the presence of the additional amino-group for subsequent reactivity, this route has not been explored further, conceivably on account of the difficulties normally associated with the synthesis of a well-defined CNH complex and the use of an isocyanide as the amino group source.…”