No abstract

Several new aspects of the chromyl chloride oxidation of olefins are presented. By carrying the reactions out at low temperature and by running a variety of control experiments, it is concluded that the three primary products of these oxidations are epoxide, chlorohydrin, and, in some cases, vicinal dichloride. All three of these products result from cis-addition processes. It is argued that these facts are not easily accommodated by any of the literature mechanisms for these oxidations. A new mechanism is proposed whose key feature is the involvement of organometallic intermediates having Cr C a bonds. To the best of our knowledge, this is the first time that organometallic species have been suggested as intermediates in the oxidations of olefins by high valent (d°) transition metal reagents. The possibility that organometallic intermediates may play a general role in the reactions of olefins and hydrocarbons with all high valent transition metal oxidants is discussed.Certain oxo metal compounds (e.g., 1-4) play a special role in organic synthesis because of their ability to selectively attach oxygen atoms to olefins and other organic substrates.

An efficient process for dynamic kinetic resolution of amines was developed by combining a ruthenium-catalyzed racemization with a lipase-catalyzed resolution. A variety of unfunctionalized primary amines were transformed into one enantiomer of the amide in high yield and high enantioselectivity.