Synfacts 2005(1): 0112-0112  
DOI: 10.1055/s-2005-872211
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

Tandem Cyclization of Allenenes to Tri- and Tetracyclic Heterocycles

Contributor(s): Victor Snieckus, Justin-Alexandre Morin
H. Ohno*, K. Miyamura, T. Mizutani, Y. Kadoh, Y. Takeoka, H. Hamaguchi, T. Tanaka*
Osaka University, Japan
Further Information

Publication History

Publication Date:
21 September 2005 (online)


Starting from amino allenenes, available from amino alcohol in five steps, a new method for the preparation of 5,6-fused hetero­cycles is presented. The reaction, proceeding in moderate to good yields, involves insertion of an arylpalladium(II) halide into the allenic moiety, followed by intramolecular carbopalladation, and aromatic C-H bond activation. Inhibition of the β-hydride elimination, either by β-methyl substitution or, as shown, by a steric effect of the α-phenyl group, was found to be essential in promoting the tandem cyclization. The scope of this reaction includes the C-H activation of heteroaromatic systems such as furan, indole and thiophene.