Diastereoselective Synthesis of Nine-Membered Heterocycles <i>via</i>
the Cycloaddition and Sequential Rearrangement of <i>N</i>
-Vinyl Nitrones with Isocyanates
作者:Ning Zou、Ji-Wen Jiao、Yu Feng、Chun-Hua Chen、Cui Liang、Gui-Fa Su、Dong-Liang Mo
DOI:10.1002/adsc.201700685
日期:2017.10.25
A metal‐free construction of highly diastereoselective nine‐membered heterocycles is described via the cycloaddition and rearrangement of N‐vinyl‐α,β‐unsaturated ketonitrones and isocyanates. Notably, the prepared nine‐membered heterocycles afforded 2,3‐dihydropyrrolizines under heating conditions. Mechanisticstudies showed that the nine‐membered rings might undergo decarboxylation, isomerization