Ruthenium-catalyzed site-specific C−H oxyfunctionalizationof steroidal ethers with periodate or bromate as terminaloxidants in phosphate buffer provided the acid-sensitive C-16hydroxy compounds in high yields. Phosphate buffer (pH7.5) significantly inhibits formation of unwanted sideproducts generated under more acidic reaction conditions.A key example is demonstrated at the 100 g scale.