Yazarlar |
Prof. Dr. Betül KARATAŞ
Türkiye |
Isabella Hyla Kryspın
|
Rudolf Aumann
|
Özet |
Striking differences in the reactions of alkoxycarbene and thiocarbene complexes of chromium and tungsten are observed. Thus, (β-imino) ethoxycarbene complexes 10a-e, generated in situ from [(OC)5W= C(OEt)CH2R] (7a-c; R = n-Pr, Me, c-C7H7) and imidoyl chlorides R1ClC=NCHR2R3 (9a-f; R 1 = t-Bu, Ph, 2-furyl; R2 = H, Me; R3 = Me, Et, Ph), undergo a metalla(di-π-methane) rearrangement to (N-enamino)ethoxycarbene complexes 12a-e, while the corresponding (β--imino)thiocarbene complexes 11a-1, derived from [(OC)5M=C(SEt)CH2R] (8a-e; M = W, Cr; R = n-Pr, Me, c-C7H7, c-C6H7Fe-(CO) 3) and imidoyl chlorides under similar conditions, form pyrroles 16a-h and 17k,l by α-cyclization. On the basis of the calculated DFT/BP86 potential energy surfaces of the particular reaction channels it is shown that (β-imino)alkoxycarbene compounds 10 prefer a metalla(di-α-methane) rearrangement due to the kinetic stability of the (N-enamino)ethoxycarbene products, while formation of pyrroles is not favored due to the presence of high energetic stationary structures in the α-cyclization pathway. For (β-imino)thiocarbene compounds 11, on the other hand, rearranged products are kinetically unstable, and α-cyclization reactions are strongly favored on thermodynamic grounds. © 2007 American Chemical Society. |
Anahtar Kelimeler |
Makale Türü | Özgün Makale |
Makale Alt Türü | SSCI, AHCI, SCI, SCI-Exp dergilerinde yayımlanan tam makale |
Dergi Adı | Organometallics |
Dergi ISSN | 0276-7333 |
Dergi Tarandığı Indeksler | SSCI |
Makale Dili | İngilizce |
Basım Tarihi | 09-2007 |
Cilt No | 26 |
Sayı | 20 |
Sayfalar | 4983 / 4996 |
Doi Numarası | 10.1021/om700391t |
Makale Linki | http://pubs.acs.org/doi/abs/10.1021/om700391t |