“…For example, intramolecular annulation of a-carbamoyl ketene dithioacetals via PIFA-mediated N-S bond formation to give substituted isothiazol-3(2H)-ones (PIFA: phenyliodine(III) bis(trifluoroacetate)), 202 synthesis of 2-benzylthio-5-phenyl-3,4-disubstituted thiophenes through intramolecular condensation of a-oxo ketene dibenzylthioacetals, 203 synthesis of N-aryl-substituted 3,4-dihydro-2-pyridones from TiCl 4 -Et 3 N promoted cyclization of 2-(2-acetyl-1-methyl-3-oxobutyl)-N-aryl-3,3-bis(ethylthio)acrylamides, 204 and the synthesis of 2,3,5-trisubstituted furans 367 from a-formyl ketene dithioacetals 77 (Scheme 28) via Wittig reaction (to give 366) and subsequent NBS-mediated cyclization (Scheme 95, NBS: N-bromosuccinimide) are known. 140,205,206…”