• Protected indole derivative which can be lithiated selectively at the 2-position. Reaction with electrophiles, followed by cleavage of the N-sulfonyl group with NaOH, leads to 2-substituted indoles: J. Org. Chem., 38, 3324; 43, 4684 (1978); 45, 3382 (1980). Dilithiation can also take place, with the second metallation occurring at the o-position of the sulfonyl benzene ring: J. Heterocycl. Chem., 18, 807 (1981).