Synfacts 2007(11): 1186-1186  
DOI: 10.1055/s-2007-991267
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Asymmetric [3+3] Cycloaddition of Trimethylenemethane with Nitrones

Contributor(s): Hisashi Yamamoto, Joshua N. Payette
R. Shintani*, S. Park, W.-L. Duan, T. Hayashi*
Kyoto University, Japan
Further Information

Publication History

Publication Date:
23 October 2007 (online)

Significance

Previously, Trost et al. have reported the use of phosphoramidite ligands in the palladium-catalyzed asymmetric [3+2] cycloaddition of trimethylenemethane derivatives (J. Am. Chem. Soc. 2006, 128, 13328). For the first time, the authors report the corresponding asymmetric [3+3] cycloaddition reaction. Cycloadducts 3 were obtained in high yields and with high ee values with good dia­stereoselectivities. The absence of cycloadducts 4 and 5 led the authors to postulate that the initially formed Pd-TMM intermediate A rapidly isomerizes to give B, having a more stabilized benzylic anion, which subsequently undergoes cycloaddition with 2 to give 3.