ELECTROPHILIC SUBSTITUTION IN INDOLES .6. SOLVOLYSIS OF INDOLYLALKYL TOSYLATES

A series of ω-(3-indolyl)-alkyl tosylates have been prepared and their solvolyses studied under a variety of conditions. The results confirm that indole can act as a powerful neighbouring group, and that the 3-position of the indole nucleus is the primary position for electrophilic attack even when this position is already substituted. The rates of the solvolyses in aqueous acetone accord with expectations based on Winstein's classical studies in the benzene series, i.e. that the degree of participation by the indole nucleus follows the order 3 ≫ 5 > 6 ≫ 4, the numbers referring to the ring size in the intermediate spirocycle. © 1969.