Thiocarbene complexes
Başlık çevirisi mevcut değil.
- Tez No: 400363
- Danışmanlar: PROF. DR. RUDOLF AUMANN
- Tez Türü: Doktora
- Konular: Eczacılık ve Farmakoloji, Kimya, Pharmacy and Pharmacology, Chemistry
- Anahtar Kelimeler: Belirtilmemiş.
- Yıl: 2007
- Dil: İngilizce
- Üniversite: Westfälische Wilhelms-Universität Münster
- Enstitü: Eczacılık Fakültesi
- Ana Bilim Dalı: Farmasötik Kimya Ana Bilim Dalı
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: 105
Özet
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Özet (Çeviri)
Fischer carbene complexes were discovered in 1964 and since then have found broaduse as synthesis components. This was valid especially for alkoxy- and aminocarbenecomplexes. Thiocarbene complexes, however, were hardly considered in this connection sofar, as the initial investigations showed particularly that they react similarly as theisostructural alkoxycarbene complexes. The study at hand shows that this is on no accountalways the case. Substantial differences in the reaction behaviour of alkoxy- and thiocarbenecomplexes of chromium and tungsten are revealed for the first time and their reasons arepointed out. Thus, it is shown that ethoxycarbene complexes on reaction with imidoylchlorides rearrange to (N-enamino)ethoxycarbene complexes, whereas isostructuralthiocarbene complexes form only pyrroles by ?-cyclization. Both reaction ways run over (Nalkylimino)heterocarbene intermediates which are key components, however, behaved verydifferently depending on the heteroatom. Thiocarbene complexes react preferentially furtherafter a dissociative mechanism over vinylidene complexes, whereas the correspondingalkoxycarbene complexes favour associative reaction steps. In agreement with the fact thatobservation stands over (N-arylimino)heterocarbene intermediates from alkoxycarbenecomplexes afforded (N-enamino)ethoxycarbene complexes as expected, from thiocarbenecomplexes, on the other hand, quinolines were obtained. Further insertion reactions werestudied for the first time by alkynes into the Ccarbene?C? single bond of thiocarbene complexes,which proceeded with high regio- and stereoselectivity by a metalla(di-?-methane)rearrangement. In the meantime it is quite obvious that the synthesic potential of thiocarbenecomplexes is reaching above that of isostructural alkoxycarbene complexes.