Divergent reactivity of alk-5-ynylidenecyclopropanes in the presence of the 1st or the 2nd generation Grubbs’ catalysts
作者:Beatriz Trillo、Moisés Gulías、Fernando López、Luis Castedo、José L. Mascareñas
DOI:10.1016/j.jorganchem.2005.07.009
日期:2005.12
Alk-5-ynylidenecyclopropanes, by virtue of being equipped with a strained cyclopropane system, can be divergently elaborated into bicyclo[3.3.0]octenes or exocyclopropylidenecycloalkenes depending on whether they react with the first or the second generation Grubbs' ruthenium carbenes. While the highly reactive second generation system catalyses the formation of ring-closing metathesis products, the less [metathesis] active first generation carbene promotes an intramolecular [3 + 2] cycloaddition to give the bicarbocyclic skeletons. (c) 2005 Elsevier B.V. All rights reserved.
Sterically Controlled Diels-Alder Cycloadditions: Rapid Entry into the Illudin Scaffold
作者:Lars Stevens-Cullinane、Nigel T. Lucas、Bill C. Hawkins
DOI:10.1002/ejoc.201402461
日期:2014.8
Rapidentry into the tricyclic ring system of the illudin family of natural products was achieved using a Diels–Aldercycloaddition of allylidenecyclopropane 7 and various cyclic and acyclic dienophiles. The reaction proceeds with complete regioselectivity and moderate to high stereoselectivity in good to excellent chemical yields.