Figure 1. Acid-base titration profiles of sulfonium ylide (1, 5)~ sulfonium salt (4, 6) systems.(a) Sulfonium ylide la-sulfonium salt 4a (X= I);(b) lb-4b (X= I);(c) lc-4c (X= Cl);(d) 5-6 (X= I);(e) product (s\ formed by warming an aqueous trifluoroacetic acid solution of sulfonium salt 4b (initial titration of the acidic solution was with sodium hydroxide).
