Allyl-, Allenyl-, and Propargyl-Transfer Reactions through Cleavage of CC Bonds Catalyzed by an N-Heterocyclic Carbene/Copper Complex: Synthesis of Multisubstituted Pyrroles
作者:Masahiro Sai、Hideki Yorimitsu、Koichiro Oshima
DOI:10.1002/anie.201100631
日期:2011.3.28
Cat. in the bag: The pictured copper complex can promote CC bond cleavage through retro‐allylation of homoallyl alcohols to form allylcopper species. This process is applicable to catalytic allylation of aldehydes and imines with homoallyl alcohols. The method has also been extended to regioselective allenylation and propargylation of imines.
Preparation of 1,2-Diaryl(heteroaryl)pyrroles and -3-methylpyrroles from <i>N</i>-Allylbenzotriazole
作者:Alan R. Katritzky、Lianhao Zhang、Jiangchao Yao、Olga V. Denisko
DOI:10.1021/jo000885x
日期:2000.11.1
Numerous 1,2-diaryl(heteroaryl)pyrroles and -3-methylpyrroles were prepared in a two-step procedure from N-allylbenzotriazoles via intramolecular oxidative cyclization in the presence of Pd(II) catalyst.
A new metal-free synthesis of pyrrole from allyl ketone and amine has been established. The reaction proceeds via an thiolative activation of the C–C double bond with dimethyl(methylthio)sulfonium trifluoromethanesulfonate, followed by a nucleophilic ring-opening addition of primary amine to the generated episulfonium intermediate, and then an internal condensation and aromatization. This mild procedure
The aldol products formed by the reaction between alpha-(N-benzyl or N-Cbz)amino aldehydes and lithium enolates of various ketones, were subjected to hydrogenolysis to give polysubstituted pyrroles in good yields (50-91%). The scope and limitations of this methodology are explored. (C) 2001 Elsevier Science Ltd. All rights reserved.
Treibs; Derra, Justus Liebigs Annalen der Chemie, 1954, vol. 589, p. 174