TY - JOUR
T1 - Alkylation of Position C‐5 of Triacetic Acid Lactone by [2,3] Sigmatropic Rearrangement of Sulphonium Ylides
AU - March, Pedro De
AU - Moreno‐Mañas, Marcial
AU - Ripoll, Isabel
PY - 1987/1/1
Y1 - 1987/1/1
N2 - Reactions of the 4‐methoxy‐6‐(phenylthiomethyl)‐2H‐pyran‐2‐ones 4 with three different diazo compounds under copper or rhodium catalysis give the corresponding sulphonium ylides, which through [2,3] sigmatropic rearrangement and further prototropy afford the pyrones 6, functionalized at the difficutly accessible position C‐5. Desulphurations of products 6 with deactivated Raney nickel give the pyrones 17–19. The influence of the experimental conditions on the competition between [2,3] sigmatropic and Stevens rearrangement has been studied for the reaction of 4‐methoxy‐6‐(phenylthiomethyl)‐2H‐pyran‐2‐one (4a) and dimethyl diazomalonate. Several products (9, 10, and 11) arising from sulphonium ylides equilibration and radical recombination have been found in addition to the [2,3] sigmatropic and the Stevens rearrangement products 6d and 8. Copyright © 1987 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
AB - Reactions of the 4‐methoxy‐6‐(phenylthiomethyl)‐2H‐pyran‐2‐ones 4 with three different diazo compounds under copper or rhodium catalysis give the corresponding sulphonium ylides, which through [2,3] sigmatropic rearrangement and further prototropy afford the pyrones 6, functionalized at the difficutly accessible position C‐5. Desulphurations of products 6 with deactivated Raney nickel give the pyrones 17–19. The influence of the experimental conditions on the competition between [2,3] sigmatropic and Stevens rearrangement has been studied for the reaction of 4‐methoxy‐6‐(phenylthiomethyl)‐2H‐pyran‐2‐one (4a) and dimethyl diazomalonate. Several products (9, 10, and 11) arising from sulphonium ylides equilibration and radical recombination have been found in addition to the [2,3] sigmatropic and the Stevens rearrangement products 6d and 8. Copyright © 1987 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
U2 - 10.1002/cber.19871200819
DO - 10.1002/cber.19871200819
M3 - Article
SN - 0009-2940
VL - 120
SP - 1413
EP - 1419
JO - Chemische Berichte
JF - Chemische Berichte
IS - 8
ER -