Enhancement of cyclopropanation chemistry in the silver-catalyzed reactions of aryldiazoacetates

AgSbF6 is an effective catalyst for the reactions of donor/acceptor substituted carbenoids and shows a very different reactivity profile from the traditional rhodium-catalyzed reactions. Most notably, cyclopropanation of sterically hindered alkenes is favorable, and products due to a Wolff rearrangement are not observed. Yields of products obtained are often high (54-96%) with excellent diastereoselectivity (> 94% de).