Previous transition metal-catalyzed synthesis processes of δ-diketones are plagued by the high cost of the rhodium catalyst and harsh reaction conditions. Herein a low-cost, roomtemperature ruthenium catalytic method is developed based on the coupling of α-keto sulfoxoniumylides with cyclopropanols. The mild protocol features a broad substrate scope (47 examples) and a high product yield (up to 99%)
A convenient new method was developed to prepare two types of vinyl cyclopropane derivatives through gold-catalyzed cyclization of 1-alkynyl cyclopropyl tert-butyl carbonates 2. Different from the previous reported 5-exo-dig route, the 6-endo-dig addition is the preferred pathway to provide six-membered cyclized carbonates. Two factors, including stereoelectronic effect and steric effect might affect