Ruthenium/TFA-catalyzed coupling of activated secondary propargylic alcohols with cyclic 1,3-diones: furan versus pyran ring formation.
A catalytic system consisting of the 16-electron allyl-ruthenium(II) complex [Ru(eta(3)-2-C3H4Me)(CO)(dppf)][SbF6] (dppf = 1,1'-bis(diphenylphosphino)ferrocene) and trifluoroacetic acid (TFA) has been used to promote the coupling between secondary propargylic alcohols and cyclic 1,3-diketones. The nature of the resulting products was found to be dependent on the ring size of the dicarbonyl compound employed. Thus, whereas 6,7-dihydro-5H-benzofuran-4-ones have been selectively obtained starting from 1,3-cyclohexanediones, via furan-ring formation, the use of 1,3-cyclopentanedione leads instead to 6,7-dihydro-4H-cyclopenta[b]pyran-5-ones via a pyran-ring formation process.
Cadierno
Victorio
V
Departamento de Química Orgánica e Inorgánica, Instituto Universitario de Química Organometálica Enrique Moles (Unidad Asociada al CSIC), Facultad de Química, Universidad de Oviedo, E-33071 Oviedo, Spain. vcm@uniovi.es
Díez
Josefina
J
Gimeno
José
J
Nebra
Noel
N
D000480:Alkynes / Q000138:chemical synthesis* / Q000737:chemistry; D001554:Benzene / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D003517:Cyclopentanes / Q000737:chemistry; D005663:Furans / Q000737:chemistry*; D015394:Molecular Structure; D020005:Propanols / Q000138:chemical synthesis* / Q000737:chemistry; D011714:Pyrans / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D014269:Trifluoroacetic Acid / Q000737:chemistry*
D000480:Alkynes; D003517:Cyclopentanes; D005663:Furans; D020005:Propanols; D011714:Pyrans; D012428:Ruthenium; D014269:Trifluoroacetic Acid; C028255:propargyl alcohol; D001554:Benzene; C039281:furan