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Synthesis of 1,3-Dihydro-2-benzofurans

Recent Literature

A convenient method enables the preparation of arylmagnesium reagents bearing an ortho-chloromethyl group. These reagents proved to be very useful for preparing various functionalized heterocycles such as isobenzofurans, phthalimidines, and benzoazepines.
T. Delacroix, L. Bérillon, G. Cahiez, P. Knochel, J. Org. Chem., 2000, 65, 8108-8110.

A nucleophilic substitution of alkyl fluorides was achieved in intramolecular reactions with O- and N-nucleophiles. The reaction is influenced by the nature of nucleophiles, the size of the ring to be formed, and the comformational rigidity of the precursors.
L. Zhang, W. Zhang, J. Liu, J. Hu, J. Org. Chem., 2009, 74, 2850-2853.

Using a cinchona squaramide-based organocatalyst, an enantioselective intramolecular oxa-Michael reaction of enones as well as α,β-unsaturated esters containing benzylic alcohols provided their corresponding 1,3-dihydroisobenzofuranyl-1-methylene ketones and 1,3-dihydroisobenzofuranyl-1-methylene esters in excellent yields with high enantioselectivities.
E. C. Son, S. Y. Kim, S.-G. Kim, J. Org. Chem., 2021, 86, 6826-6839.

The use of i-PrOH as environmentally benign hydrogen surrogate enables a ligand-free Co-catalyzed chemoselective reductive cyclization cascade of enone-tethered aldehydes. The selectivity between Michael-Aldol cycloreduction cascade and oxa-Michael cascade can be adjusted by the addition of TEMPO as a steric Lewis bases to provide 1H-indenes and dihydroisobenzofurans, respectively.
S.-S. Ma, B.-L. Jiang, Z.-K. Yu, S.-J. Zhang, B.-H. Xu, Org. Lett., 2021, 23, 3873-3878.