A new and efficient synthesis of 4-functionalized benzo[b]furans from 2,3-dihalophenols.
Tandem Sonogashira coupling/5-endo-dig cyclization reactions on 2,3-dihalophenols suppose a straightforward entry to 4-halobenzo[b]furans, which can be easily transformed into 4-functionalized benzo[b]furans, that are difficult to synthesize by other procedures. On the other hand, the starting 2,3-dihalophenols are efficiently prepared from commercially available 3-halophenols, via their N,N-diethyl carbamates by selective lithiation at the 2-positions by treatment with s-BuLi/TMEDA or LDA at low temperature and reaction with halogen electrophilic reagents.
Sanz
Roberto
R
Departamento de Química, Area de Química Orgánica, Facultad de Ciencias, Universidad de Burgos, Pza. Missael Bañuelos s/n, 09001-Burgos, Spain. rsd@ubu.es
Castroviejo
M Pilar
MP
Fernández
Yolanda
Y
Fañanás
Francisco J
FJ
D001554:Benzene / Q000737:chemistry*; D002219:Carbamates / Q000737:chemistry; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry*; D006846:Hydrocarbons, Halogenated / Q000737:chemistry*; D006868:Hydrolysis; D015394:Molecular Structure
D002219:Carbamates; D005663:Furans; D006846:Hydrocarbons, Halogenated; D001554:Benzene