Hydrazinolysis of the pentacarbonyl[alkyl- or aryl-(methoxy)carbene] complexes of W0 and Cr0 with both 1,1- and 1,2-disubstituted hydrazines affords the corresponding new hydrazinocarbenes 15–18, 21 and 22, and the presence of LiCl in the reaction medium greatly increases their yields.
Gold acyls and imidoyls prepared from anionic Fischer-type carbene complexes
作者:Helgard G. Raubenheimer、Matthias W. Esterhuysen、Catharine Esterhuysen
DOI:10.1016/j.ica.2005.03.029
日期:2005.11
Reaction of [(CO) 5 WC(O)Ph]Li or [(CO) 5 WC(O)Ph]NBu 4 with Ph 3 PAuCl affords acyl complexes of gold. In the latter conversion, both the crystalline products [(CO) 5 WCl]NBu 4 ( 2 ) and Ph 3 PAuC(O)Ph ( 3 ) have been isolated and fully characterised. Similarly, imidoyl gold compounds ( 4 – 8 ) result from deprotonated aminocarbene complexes, [(CO) 5 MC(NR 2 )R 1 ]Li (M = Cr, W; R 1 = Ph, Me; R 2
Reaction of aminocarbene complexes of chromium with alkynes. 1. Formation and rearrangement of ketene and nitrogen ylide complexes
作者:Evelyne Chelain、Regis Goumont、Louis Hamon、Andree Parlier、Michele Rudler、Henri Rudler、Jean Claude Daran、Jacqueline Vaissermann
DOI:10.1021/ja00047a018
日期:1992.10
The title reactions of chromium-containing carbene complexes (CO)5Cr=C(R1)N(R2R3) (R1 = H, Me, Ph; R2 = Me; R3 = Me, C3H5, CH2C3H5; R2R3 = (CH2)5) 8 and (CO)5Cr=C[(CH2)3C=CPh]N(R1R2) (R1 = R2 = Me; R1R2 = (CH2)5; R1R2 = (CH2)4) 9, bearing alkyl groups of low migratory aptitude on nitrogen, have been examined. In contrast to complexes in which nitrogen bears either an alkyl and an allyl or a benzyl group or is part of a strained cycle, which give heterocycles upon alkyne/CO insertions followed by nitrogen-to-carbon migrations (e.g., 1 --> 7), complexes 8 and 9 lead to stable nitrogen ylides, which could be fully characterized by X-ray crystallography in the case of 8a and 9a. Moreover, in the case of complexes of the general structure 9, ketene precursors of the ylides could either be detected (R1 = Me; R2 = CH2Ph) or isolated and characterized (R2R3 = (CH2)5). The new ylide complexes undergo, upon moderate heating, Stevens-type rearrangements to the expected heterocyclic compounds as a result of nitrogen-to-carbon migrations of various alkyl groups, and upon treatment with dimethyldioxirane, they undergo oxidation to lactone complexes.