The first metal-catalyzed intramolecular [5+2] cycloadditions of vinylcyclopropanes and alkenes: Scope, stereochemistry, and asymmetric catalysis

The first studies of the metal-catalyzed [5+2] cycloadditions of vinylcyclopropanes and alkenes are described. These reactions proceed with exceptional diastereoselectivity and in good to excellent yields. The effect of tether and substituent variations are examined. In addition, preliminary studies show that enantioselective cycloadditions can be achieved through the use of catalysts modified with chiral phosphine ligands. This novel, general, and efficient procedure provides a fundamentally new approach to the synthesis of a variety of products of structural and medicinal significance.