Interrupted Nazarov Reactions Using Dichlorocyclopropanes: A Novel Mode of Arene Trapping
作者:Tina N. Grant、F. G. West
DOI:10.1021/ol7015669
日期:2007.9.1
2-Siloxy-2-alkenyl-1,1-dichlorocyclopropanes with aryl-terminated side chains undergo silver-assisted electrocyclic opening/Nazarov cyclization. The resulting 2-siloxycyclopentenyl cations are intercepted by the pendant arenes to furnish tricyclic adducts in moderate to good yields. In cases where the arene trap was tethered through the cyclopropane unit, a new mode of trapping occurred to generate unique bridged carbon frameworks.
A New Approach to the Nazarov Reaction via Sequential Electrocyclic Ring Opening and Ring Closure
作者:Tina N. Grant、F. G. West
DOI:10.1021/ja063421a
日期:2006.7.1
furnishes vinylcyclopropanol silyl ethers in good yield. Treatment with silver(I) at room temperature effects disrotatory electrocyclic opening to a 2-chloro-3-silyloxypentadienyl cation, which then undergoes conrotatory (Nazarov) electrocyclization to provide chlorocyclopentenones. This two-step sequence offers a convenient and mild alternative to the standard Nazarovcyclization protocol via a formal 4+1