Stereoselectivity in the TiCl4-Catalyzed [4+2] Cycloaddition of Cyclopentadiene to (2R)-Bornane-10,2-sultam Derivatives of Fumaric Acid Monoesters
作者:Michal Achmatowicz、Christian Chapuis、Piotr Rzepecki、Janusz Jurczak
DOI:10.1002/(sici)1522-2675(19990210)82:2<182::aid-hlca182>3.0.co;2-p
日期:1999.2.10
The [4 + 2] cycloaddition of cyclopentadiene to the (2R)-bornane-10,2-sultam derivative (-)-1b of fumaric monomethyl ester proceeds with high endo and pi-facial diastereoselectivity in the presence of 0.5 mol-equiv. of TiCl4. The major diastereoisomer endo-(2R,3R)-2b, isolated in 87% yield by crystallization, was subjected to X-ray crystal-structure analysis. Steric influence of ethyl- and benzyl-ester analogues (-)-1c and (-)-1d, respectively, is also reported.