Rh-Catalyzed [4+2] Annulation of 4-Alkynals with Isocyanates and Its Application to the Parallel Kinetic Resolution of Unfunctionalized 4-Alkynals
作者:Ken Tanaka、Yuji Hagiwara、Masao Hirano
DOI:10.1002/anie.200504470
日期:2006.4.21
Synthesis of substituted 6-imino-2-piperidinones by Rh-catalyzed [4+2] annulation of 4-alkynals with carbodiimides
作者:Ken Tanaka、Marina Mimura、Daiki Hojo
DOI:10.1016/j.tet.2009.06.115
日期:2009.10
Synthesis of substituted 6-imino-2-piperidinones has been achieved by cationic rhodium(1)/dppp complex-catalyzed [4+2] annulations of various 4-alkynals with carbodiimides at room temperature. The reactions of benzene-linked 4-alkynals (2-alkynylbenzaldehydes) and carbodiimides also proceeded at room temperature, affording the corresponding 6-imino-2-piperidinones. (C) 2009 Elsevier Ltd. All rights reserved.
Rhodium-Catalyzed Synthesis of Cyclohexenones via a Novel [4 + 2] Annulation
作者:Ken Tanaka、Gregory C. Fu
DOI:10.1021/ol017308v
日期:2002.3.1
[GRAPHICS]In the presence of a rhodium catalyst, 4-alkynals react with alkynes to furnish cyclohexenones, presumably via metalacycle 1; as far as we are aware, this is the first example of the generation of this class of compounds through such a transformation. In view of the easy accessibility of 4-alkynals (alkynylmetal + alpha,beta-unsaturated aldehyde) and alkynes, this [4 + 2] cyclization constitutes an interesting new approach to functionalized cyclohexenones.