An improved method for the synthesis of γ-lactones using sodium bromate and sodium hydrogen sulfite was written by Hayat, S.;Atta-ur-Rahman;Choudhary, M. I.;Khan, K. M.;Bayer, E.. And the article was included in Tetrahedron Letters in 2001.Safety of 5-Methylisobenzofuran-1(3H)-one This article mentions the following:
2-Alkylbenzoic acids are treated with a NaBrO3/NaHSO3 reagent under in a 2-phase system using AcOEt as solvent, under mild conditions to give the corresponding phthalides in moderate to satisfactory yield. Intermediately, α-brominated alkylbenzoic acids are formed by in-situ generated HOBr. These α-brominated acids undergo an intramol. nucleophilic substitution to afford the corresponding γ-lactones. In the experiment, the researchers used many compounds, for example, 5-Methylisobenzofuran-1(3H)-one (cas: 54120-64-8Safety of 5-Methylisobenzofuran-1(3H)-one).
5-Methylisobenzofuran-1(3H)-one (cas: 54120-64-8) belongs to benzofurans derivatives. Benzofurans are compounds with a planar structure having 10 pi electrons that include the lone pair on oxygen atom, which makes it more susceptible to electrophilic attack. Introduction of benzofurans in organic synthesis, particularly drug synthesis, involves generally the use of their metalated species as nucleophiles in addition reactions or in metal-catalysed cross-coupling reactions.Safety of 5-Methylisobenzofuran-1(3H)-one
Referemce:
Benzofuran – Wikipedia,
Benzofuran | C8H6O – PubChem