The silylation of the known compound FK-520 by means of tert-butyldimethylsilyl chloride (TBDMS-Cl) and imidazole in DMF gives the disilylated compound (II), which is selectively monodesilylated by means of 40% HF in acetonitrile for 2 h at 0 C yielding the monosilylated compound (III). The chlorination of (III) by means of triphenylphosphine in refluxing CCl4 gives the chloro derivative (IV), which is finally desilylated with 40% HF in acetonitrile at room temperature.

The silylation of the known compound FK-520 by means of tert-butyldimethylsilyl chloride (TBDMS-Cl) and imidazole in DMF gives the disilylated compound (II), which is selectively monodesilylated by means of 40% HF in acetonitrile for 2 h at 0 C yielding the monosilylated compound (III). The chlorination of (III) by means of triphenylphosphine in refluxing CCl4 gives the chloro derivative (IV), which is finally desilylated with 40% HF in acetonitrile at room temperature.

The silylation of the known compound FK-520 by means of tert-butyldimethylsilyl chloride (TBDMS-Cl) and imidazole in DMF gives the disilylated compound (II), which is selectively monodesilylated by means of 40% HF in acetonitrile for 2 h at 0 C yielding the monosilylated compound (III). The chlorination of (III) by means of triphenylphosphine in refluxing CCl4 gives the chloro derivative (IV), which is finally desilylated with 40% HF in acetonitrile at room temperature.