IQUIR   05412
INSTITUTO DE QUIMICA ROSARIO
Unidad Ejecutora - UE
artículos
Título:
Efficient Synthesis of 4-Sulfanylcoumarins from 3-Bromocoumarins via a Highly Selective DABCO-Mediated One-pot Thia-Michael Addition/elimination Process
Autor/es:
DILELIO, M. C.; MOSTARDEIRO, V.; SILVEIRA, C. C.; KAUFMAN, T. S.
Revista:
RSC Advances
Editorial:
Royal Socyety of Chemistry
Referencias:
Lugar: Londres; Año: 2020 vol. 10 p. 482 - 491
ISSN:
2046-2069
Resumen:
A facile and efficient protocol for the highly selective direct sulfanylation of 3-bromocoumarins under DABCO promotion, was developed. The transformation took place with aromatic and aliphatic thiols aswell as with a,u-dithiols, affording the expected products in very good to excellent yields. Simple andconvenient ways to access 4-((u-mercaptoalkyl) thio)coumarins and the dimeric 4,40-(alkane-1,4-diylbis(sulfanediyl))bis(coumarins) were also devised with the use of a,u-alkanedithiols in different ratioswith regards to the starting 3-bromocoumarin. The transformation seems to proceed through the DABCO-mediated thia-Michael stereoselective addition of the thiolate anion to the a,b-unsaturated carbonyl system of the coumarin, followed by a DABCO-assisted stereoselective dehydrobromination of the resulting a-bromo carbonyl intermediate.