TRI(INDOLYL)PHOSPHINE OXIDES - ATTEMPTED FORMATION OF LOWER RIM-CAPPED CONE CONFORMERS OF CALIX[3]INDOLES

3-(p-Chlorophenyl)-4,6-dimethoxyindole (1a), 3-(p-bromophenyl)-4, 6-di methoxyindole (1b), 5-benzyloxyindole (1c), and indole (1d) yield the corresponding tri(indolyl)phosphine oxides (2a-d), on sequential treat ment with n-butyllithium and phosphoryl chloride. The related phosphin es, arsines, and stibines were not isolated. The stibine from indole ( 1a) is implicated as a reactive intermediate in the formation of the c alix[3]indole (5), following its interaction with formaldehyde. (C) 19 96 John Wiley & Sons, Inc.