30971-68-7Relevant articles and documents
Behavior of group 6 fischer aminocarbene complexes in a supercharged medium: A single electron transfer-H atom transfer process
Lage, Marta L.,Mancheno, Maria J.,Martinez-Alvarez, Roberto,Gomez-Gallego, Mar,Fernandez, Israel,Sierra, Miguel A.
, p. 2762 - 2772 (2009/09/30)
The ESI-MS study of the ionization of a series of aryl, alkenyl, and alkynyl (Fischer) aminocarbene complexes is described. The process requires the initial capture of one electron from the ESI source, followed by the transfer of a hydrogen atom to the additive (TTF or Cs2CO3). Regardless of their structure, both NH and N,N-disubstituted aminocarbenes can effectively ionize under ESI-MS conditions, as long as they have abstractable H atoms. Overall, the process can be envisaged as a single electron transfer-H atom transfer process. The experimental findings are supported by DFT calculations. The ESI-MS ionization of bis-alkynylaminocarbene complexes follows the same patterns. However, the [M - H]- ions evolve by arylacetylene extrusion together with the usual sequence of CO loss. The process requires the presence of a free NH group and occurs by intramolecular hydrogen transfer from the NH to the metal center. Bis-aminocarbenes having rigid tethers between the nitrogen atoms or lacking free NH groups do not produce this fragmentation.
Reaction of aminocarbene complexes of chromium with alkynes. 1. Formation and rearrangement of ketene and nitrogen ylide complexes
Chelain, Evelyne,Goumont, Regis,Hamon, Louis,Parlier, Andrée,Rudler, Michèle,Rudler, Henri,Daran, Jean-Claude,Vaissermann, Jacqueline
, p. 8088 - 8098 (2007/10/02)
The title reactions of chromium-containing carbene complexes (CO)5Cr=C(R1)N(R2R3) (R1 = H, Me, Ph; R2 = Me; R3 = Me, C3H5, CH2C3H
Organic Syntheses with Transition Metal Complexes, 48. - Methyl Thiocarbene and Alkenyl Thiocarbene Chromium Complexes: Synthesis and Reactions
Aumann, Rudolf,Schroeder, Jochen
, p. 2053 - 2058 (2007/10/02)
Thiocarbene chromium complexes (CO)5Cr=C(SR1)R (4: R = Me, Ph; R1 = c-C6H11, CH2CH=CH2, C2H5, C6H5) were readily obtained in up to 97 percent isolated yields from the corresponding ethoxycarbene chromium complexes 5a,b and thiols 6 in methanol in the presence of Na2CO3 as a catalyst.Reaction conditions, which lead to unfavorable side products, like thioacetals 8 and/or thioenol ether 10, are discussed.Methyl thiocarbene complexes 4b-d undergo a facile aldol condensation with the aromatic aldehydes 14 or 16 to give alkenyl thiocarbene complexes 15b-d and 17, respectively.The Cr=C bonds of 15 prove to be reactive towards the insertion of isocyanides or oxygen.Thus, on addition of two equivalents of the isocyanide 18 to 15d, 1-aza-1,2,4-pentatriene 20 is obtained.The oxidative decomposition of 15d on silica gel leads to the formation of thioester 25 and thioindene 26.Characteristic differences in the reactivity of thiocarbene complexes and ethoxycarbene complexes are discussed.
