Synthesis of α‐Nitro‐α‐diazocarbonyl Derivatives and Their Applications in the Cyclopropanation of Alkenes and in O?H Insertion Reactions

A facile and highly efficient method for the preparation of α‐nitro‐α‐diazocarbonyl derivatives by a diazo‐transfer reaction involving (trifluoromethyl)sulfonyl azide has been developed. These substrates undergo a rhodium‐catalyzed cyclopropanation reaction with a variety of alkenes. A systematic study of the reaction indicated that the diastereoselectivity of the cyclopropanation could be effectively controlled through the modification of the steric bulk of the diazo reagent. A novel O? H insertion reaction of the metal? carbene complex derived from the α‐nitro‐α‐diazocarbonyl reagent afforded the corresponding novel α‐nitro‐α‐alkoxy carbonyl derivatives.