The 6-substituted 3-bromo-5-iodo-2(2H)-pyranones, prepared by iodolactonization of the corresponding 5-substituted (E)-2-bromo-2-en-4-ynoic acids 10, were used as precursors to 5,6-disubstituted 3-methyl-2(2H)-pyranones and 6-substituted 3-methyl-2(2H)-pyranones . The synthesis of compounds involved two consecutive Stille-type reactions, whereas the approach followed to prepare compounds consisted of the selective reduction of the dihalogen derivatives to the corresponding 6-substituted 3-bromo-2(2H)-pyranones , followed by a Pd/Cu-catalysed reaction with tetramethyltin. However, this synthetic approach to compounds proved to be unsuitable for preparing stereoisomerically pure fusalanipyrone, a natural product isolated from Fusarium solani. Nevertheless, this compound which is a natural product isolated from Gibberella fujikuroi, could be synthesized in stereoisomerically pure form by reaction sequences involving iodolactonization of easily available (2Z,6Z)- and (2Z,6E)-2,6-dimethyl-2,6-octadien-4- ynoic acids, followed by Pd catalysed triethylammonium formate reduction of the thus obtained 6-substituted 5-iodo-3-methyl-2(2H)-pyranones
Selective synthesis of 5,6-disubstituted 3-methyl-2(2H)-pyranones and 6-substituted 3-methyl-2(2H)-pyranones, including fusalanipyrone and gibepyrone A / Matteo, Biagetti; Fabio, Bellina; Adriano, Carpita; Stephane, Viel; Mannina, Luisa; Renzo, Rossi. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1434-193X. - ELETTRONICO. - 2002:6(2002), pp. 1063-1076. [10.1002/1099-0690(200203)2002:6<1063::aid-ejoc1063>3.0.co;2-m]
Selective synthesis of 5,6-disubstituted 3-methyl-2(2H)-pyranones and 6-substituted 3-methyl-2(2H)-pyranones, including fusalanipyrone and gibepyrone A
MANNINA, LUISA;
2002
Abstract
The 6-substituted 3-bromo-5-iodo-2(2H)-pyranones, prepared by iodolactonization of the corresponding 5-substituted (E)-2-bromo-2-en-4-ynoic acids 10, were used as precursors to 5,6-disubstituted 3-methyl-2(2H)-pyranones and 6-substituted 3-methyl-2(2H)-pyranones . The synthesis of compounds involved two consecutive Stille-type reactions, whereas the approach followed to prepare compounds consisted of the selective reduction of the dihalogen derivatives to the corresponding 6-substituted 3-bromo-2(2H)-pyranones , followed by a Pd/Cu-catalysed reaction with tetramethyltin. However, this synthetic approach to compounds proved to be unsuitable for preparing stereoisomerically pure fusalanipyrone, a natural product isolated from Fusarium solani. Nevertheless, this compound which is a natural product isolated from Gibberella fujikuroi, could be synthesized in stereoisomerically pure form by reaction sequences involving iodolactonization of easily available (2Z,6Z)- and (2Z,6E)-2,6-dimethyl-2,6-octadien-4- ynoic acids, followed by Pd catalysed triethylammonium formate reduction of the thus obtained 6-substituted 5-iodo-3-methyl-2(2H)-pyranonesI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.