Synthesis of o-Carboxyarylacrylic Acids by Room Temperature Oxidative Cleavage of Hydroxynaphthalenes and Higher Aromatics with Oxone

Abstract

A simple procedure for the synthesis of a variety of o-carboxyarylacrylic acids has been developed with Oxone (2KHSO5·KHSO4·K2SO4); the oxidation reaction involves the stirring of methoxy/hydroxy-substituted naphthalenes, phenanthrenes, anthracenes, etc. with Oxone in an acetonitrile-water mixture (1:1, v/v) at rt. Mechanistically, the reaction proceeds via initial oxidation of naphthalene to o-quinone, which undergoes cleavage to the corresponding o-carboxyarylacrylic acid. The higher aromatics are found to yield carboxymethyl lactones derived from the initially formed o-carboxyarylacrylic acids.

Study of the Oxidative Cleavage Proposed in the Biogenesis of Transtaganolides/Basiliolides: Pyran‐2‐one Aromaticity‐Mediated Regioselective Control and Biogenetic Implications

“…A plausible mechanism for 24 involving the oxidative cleavage between the positions C5 and C6 is outlined in Scheme . The assay with grevillone ( 1a ) did not produce reaction as it is reported in the literature . The dimethyl ester 19 was obtained from umbelliferone ( 1b ) in 9 % yield, and also from daphnetin ( 1h ) in 20 % yield, demonstrating that 1h is a reaction intermediate in the oxidation of umbelliferone ( 1b ) as it was proposed in Scheme .…”

“…The assay with grevillone (1a) did not produce reaction as it is reported in the literature. [25] The dimethyl ester 19 was obtained from umbelliferone (1b) in 9 % yield, and also from daphnetin (1h) in 20 % yield, demonstrating that 1h is a reaction intermediate in the oxidation of umbelliferone (1b) as it was proposed in Scheme 10. Assays with 4-methylisoscopoletin (1c) or 4-methylscopoletin (1d) required huge amounts of oxidant, and a mixture of dimethyl 2-methoxyfumarate (26) and dimethyl citraconate (27) was obtained in low yield as result of overoxidation.…”

“…Reaction crudes were methylated by acid catalysis in MeOH. (25) in low yields. A plausible mechanism for 24 involving the oxidative cleavage between the positions C5 and C6 is outlined in Scheme 11.…”

“…Firstly we focused our attention on Oxone® that recently has showed great efficiency to promote oxidative fissions of aromatic rings . Umbelliferone ( 1b ) was treated with this peroxyacid and acetone in basic medium because these conditions are well‐known as generator system of dimethyldioxirane in situ, another effective oxidant to carry out the cleavage of benzene rings,[12c] and therefore, to take advantage of the oxidizing capacity of two different reagents.…”

Sequential Silver‐Catalyzed Oxidative Cyclization Reactions of Unprotected 2‐Alkynylanilines to Anthranils

“…Benzylic alcohols are more prone to oxidation by Oxone . Therefore, the further oxidative cleavage of the 1,2‐dione 4cj that occurs under our reactions conditions limits its synthetic utility.…”