119567-47-4Relevant academic research and scientific papers
α-Addition von Aminen, Iminen und Hydrazinen an Allenyliden-Komplexe - Bildung von Carben-, Azetidinyliden- und Nitril-Komplexen
Fischer, Helmut,Roth, Gerhard,Reindl, David,Troll, Carsten
, p. 133 - 149 (2007/10/02)
Diarylallenylidene(pentacarbonyl)-chromium and -tungsten complexes, (CO)5M=C=C=CR2 (M = W (1), Cr (2)), react with amines, imines and hydrazines by addition of the nitrogen nucleophile to the Cα allenylidene atom.With NEt3 the adduct formation is reversible.With secondary and primary amines, imines and hydrazines, the initially formed N-ylide complexes react readily further to give carbene, azetidinylidene and nitrile complexes, respectively.For example the reaction of (a) 1 and 2 with HNEt2 or H2NPh gives alkenyl(amino)carbene complexes, (CO)5M=CNR2' (3-5); (b) of 1 and 2 with HN=CR2' gives alkenyl(alkylideneamino)carbene complexes, (CO)5M=C (6,7); (c) of 1 with (i-Pr)N=C(Ph)H the azetidinylidene complex 9; (d) of 1 with 1,2-disubstituted hydrazines such as H(Me)NN(R)H (R = Me, Ph) alkenyl(hydrazino)carbene complexes, (CO)5W=C (11) and (e) of 1 with H2NNR1R2 (R1 = R2 = H, Me; R1 = H, R2 = Ph) alkenyl(amino)carbene complexes (13) and/or acrylnitrile complexes, (CO)5W(NC-C(H)=CR2> (12).The structures of representative examples of 6, 11 and 12 were established by X-ray analyses.
Synthesis of [Alkenyl(dimethylamino)carbene]tungsten complexes using the peterson reaction: X-ray crystal structure of (E)-(CO)5W[C(NMe2)CH=CH(η-C5H 4)Fe(η-C5H5)]
Macomber, David W.,Madhukar, Puttannachetty,Rogers, Robin D.
, p. 1275 - 1282 (2008/10/08)
Treatment of (CO)5W[C(NMe2)CH3] (1) with n-BuLi followed by Me3SiCl produced (CO)5W[C-(NMe2)CH2SiMe3] (2) in 90% yield. (CO)5W[C(NMe2)CHSiMe3]Li, which was formed in the reaction between 2 and n-BuLi, reacted with several nonenolizable aldehydes or ketones to afford moderate yields (45-61%) of the desired (alkenylaminocarbene)tungsten complexes (CO)5W[C(NMe2)CH=CR1R2] (3a-f) (a, R1 = R2 = H; b, R1 = H, R2 = Ph; c, R1 = H, R2 = 2-furyl; d, R1 = H, R2 = trans-CH=CHPh; e, R1 = H, R2 = (η-C5H4)Fe(η-C5H5); f, R1 = R2 = Ph). For compounds 3b-e, exclusive formation of the E isomer occurred. Treatment of 2 with n-BuLi followed by either CF3SO3CH3 or CH2=CHCH2Br afforded complexes 4a and 4b (70-90%), (CO)5W[C(NMe2)CH(R)SiMe3] (4a, R = CH3; 4b, R = CH2CH=CH2), respectively. Complexes 4a or 4b could not be obtained by reacting the corresponding complexes 5a or 5b, (CO)5W-[C(NMe2)CH2R] (5a, R = CH3; 5b, R = CH2CH=CH2), with n-BuLi followed by Me3SiCl. Furthermore the lithium anions (CO)5W[C(NMe2)C(R)SiMe3]Li (R = CH3, CH2CH=CH2) from 4a or 4b did not react with aldehydes or ketones to afford the desired α-substituted (alkenylaminocarbene)tungsten complexes. One example of such a complex, (CO)5W[C(NMe2)C(CH3)=CH2] (7), could, however, be prepared in 75-80% yield by treating (CO)5W[C(OCH3)C(CH3)=CH2] (6) with HNMe2 in ether. (CO)5W[C(NMe2)CHSiMe3]Li was made to react with PhCOCl to yield the enol silyl ether derivative (CO)5W[C(NMe2)CH=C(OSiMe3)Ph] (8) (26%) along with a trace of an air-sensitive complex (CO)5W[C(NMe2)CH2C(O)Ph) (9). (E)-(CO)5W-[C(NMe2)CH=CH(η-C5H 4)Fe(η-C5H5)] (3e) was further characterized by single-crystal X-ray diffraction methods. Complex 3e crystallizes in the monoclinic space group P21/c with (at 20°C) a = 12.022 (4) A?, b = 12.857 (8) A?, c = 13.826 (8) A?, β= 102.19 (4)°, and Dcalcd = 1.88 g cm-3 for Z = 4. Least-squares refinement based on 2604 independent observed [Fo ≥ 5σ(Fo)] reflections led to a final conventional R value of 0.044.
