An improved version of the Sharpless asymmetric dihydroxylation

The osmium catalyzed asymmetric dihydroxylation of olefins (Sharpless AD) was studied under controlled pH conditions. It was found that providing a constant pH value of 12.0 leads to improved reaction rates for internal olefins. Hydrolysis aids such as methanesulfonamide can be omitted. For terminal olefins, working at a constant pH of 10.0 at room temperature leads to higher enantioselectivities compared to AD reactions without pH control.