Asymmetric Iodocyclization Catalyzed by Salen–CrIIICl: Its Synthetic Application to Swainsonine
作者:Hyo Young Kwon、Chul Min Park、Sung Bae Lee、Joo-Hack Youn、Sung Ho Kang
DOI:10.1002/chem.200701199
日期:2008.1.18
The previously developed enantioselective iodocyclization of gamma-hydroxy-cis-alkenes required 30 mol% of (R,R)-salen-Co(II) complex as chiral catalyst and 0.75 equivalent of N-chlorosuccinimide (NCS) as activator to produce 2-substituted tetrahydrofurans with 61 to 90% ee. Due to the considerable loading amount of the Co(II) complex, another more effective catalyst was pursued by screening (R,R)-salen-transition