and PhS− ions. Whereas 4a gave only SN2 products, 4b gave SN2 and E2C products typical of SN2/E2C competition. Among the salts 5a–c displacement of the benzylgroup was dominant (5a) or exclusive (5b, c), thus exhibiting the preferential displacement of a benzylgroup that has been fully documented in earlier studies of SN2 reactions. Qualitative comparison showed that 3a (methyl) reacted much faster