Artículos de revistas
First total synthesis of the only known 2- isopropyliden-2H-benzofuran-3-one isolated from V. luetzelburgii
Registro en:
1759-9679
10.1039/C6RA28587B
Autor
Kaufman, Teodoro Saúl
Bracca, Andrea Beatriz Juana
Larghi, Enrique Leandro
Pergomet, Jorgelina Leonor
Institución
Resumen
The first total synthesis of 5-(1-hydroxy-1-ethyl)-2-isopropyliden-2H-benzofuran-3-one, is reported in its
racemic and in one of its optically active [(S)-( )] forms. This heterocycle, isolated from Verbesina
luetzelburgii, is the only known 2-isopropyliden-2H-benzofuran-3-one produced by species of
Verbesina. The sequence took place in eight steps and 19% overall yield (up to 33% for the chiral form),
from 40-hydroxyacetophenone. It entailed carbonyl group protection as the 1,3-dioxolane and a phenol
ortho formylation, followed by a Williamson etherification with chloroacetone and an organocatalytic
cross-aldolization, to afford a 2-acetyl-2,3-dihydrobenzofuran-3-ol intermediate. The latter underwent
a methyl Grignard addition to the carbonyl moiety, followed by selective oxidation of the benzylic
alcohol and deprotection, resulting in a b-hydroxy diketone derivative. A MsCl-assisted dehydration of
the tertiary alcohol, established the isopropylidene motif, whereas the syntheses culminated by chemical
or enzymatic (carrot, celeriac) selective reductions of the exocyclic carbonyl group. Fil: Kaufman, Teodoro Saúl. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina. Fil: Bracca, Andrea Beatriz Juana. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina. Fil: Larghi, Enrique Leandro. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina. Fil: Pergomet, Jorgelina Leonor. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina.