A Gold Catalyst for Carbene-Transfer Reactions from Ethyl Diazoacetate

摘要

The use of transition-metal-based catalysts for the transfer of carbene units from diazo compounds constitutes a powerful tool in organic synthesis.Several metals have been reported to mediate this transformation effectively,and the appropriate selection of ligands has permitted excellent selectivities.Highly chemo-,diastereo-,and/or enantioselective systems have been reported with rhodium-,copper-,or cobalt-containing catalysts.In fact,nearly all 12 elements of Groups 8-11 have been found to decompose diazo compounds and transfer a carbene unit to saturated or unsatu-rated organic substrates,leading to the insertion or addition product,respectively (Scheme 1).Only one of these 12 elements remains unexplored in this chemistry:gold.Although the other members of Group 11-copper and,to a lesser extent,silver-have been described to induce such transformations,conducting this type of catalytic reaction with gold remains a challenge.We therefore focused our attention on the development of a gold-based catalyst,as a result of our experience in the area of metal-catalyzed carbene transfer from ethyl diazoacetate (EDA).