strates,
a large number of mutually complementary protective groups are needed
and, indeed, are available. In early syntheses the chemist chose a standard derivative
known to be stable to the subsequent reactions. In a synthesis of callistephin chloride
the phenolic OH group in 1 was selectively protected as an acetate.1 In the presence
of silver ion the aliphatic hydroxyl group in 2 displaced the bromide ion in a
bromoglucoside. In a fi nal step the acetate group was removed by basic hydrolysis.