Expanding the C2-symmetric bicyclo[2.2.1]hepta-2,5-diene ligand family: concise synthesis and catalytic activity in rhodium-catalyzed asymmetric addition

Guillaume Berthon-Gelloz; Tamio Hayashi

doi:10.1021/jo061385s

Expanding the C2-symmetric bicyclo[2.2.1]hepta-2,5-diene ligand family: concise synthesis and catalytic activity in rhodium-catalyzed asymmetric addition

J Org Chem. 2006 Nov 10;71(23):8957-60. doi: 10.1021/jo061385s.

Authors

Guillaume Berthon-Gelloz¹, Tamio Hayashi

Affiliation

¹ Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan.

PMID: 17081029
DOI: 10.1021/jo061385s

Abstract

New C2-symmetric bicyclo[2.2.1]hepta-2,5-dienes bearing methyl and phenyl substituents at the 2 and 5 positions were prepared enantiomerically pure through a two-step sequence starting from the readily available bicyclo[2.2.1]hepta-2,5-dione. Due to the instability or volatility of these dienes, their isolation was achieved through the formation of the corresponding stable [RhCl(diene)]2 complexes. These chiral rhodium complexes displayed high activity and enantioselectivity (up to 99% ee) in the rhodium-catalyzed 1,4-addition and 1,2-addition of phenylboronic acid to cyclic enones and N-sulfonylimines, respectively.