Nature of the Chain Propagation in the Photostimulated Reaction of 1-Bromonaphthalene with Sulfur Centered Nucleophiles

LUCIANA C. SCHMIDT; JUAN E. ARGÜELLO; ALICIA B. PEÑÉÑORY

JOURNAL OF ORGANIC CHEMISTRY

AMER CHEMICAL SOC

Año: 2007 vol. 72 p. 2936 - 2936

0022-3263

he reactivity of -SC(NH)NH2 (1), MeCOS- (2), and PhCOS- (3) toward 1-naphthyl radicals was studied in DMSO. The photostimulated reaction of anions 1, 2, and 3 with 1-bromonaphthalene (4) after quenching with MeI renders 1-(methylthio)naphthalene (6) as a main product together with bis(1-naphthyl) sulfide (7) and naphthalene (5). The thioacetate ion (2) and thiobenzoate ion (3) were unreactive toward 4 as electron-donor under photostimulation; however, in the presence of potassium tert-butoxide anion (entrainment conditions), they gave the mentioned products 5, 6, and 7, after the addition of MeI. Quenching of the triplet state of 4 was assigned as the photoinduced initiation step, with a rate constant value of (4.6 ( 0.5) _ 108 M-1 s-1 for tert-butoxide anion and a rough estimated value of (8 ( 7) _ 107 M-1 s-1 for anion 1. By using hydrogen abstraction from DMSO as the competitive reaction, the absolute rate constants for the addition of anions 1, 2, and 3 to 1-naphthyl radicals have