Sodium hypochlorite pentahydrate (NaOCl·5H2O) crystals; An effective re-oxidant for TEMPO oxidation. Issue 22 (2nd June 2016)

• Record Type: Journal Article
• Authors: Okada, Tomohide; Asawa, Tomotake; Sugiyama, Yukihiro; Iwai, Toshiaki; Kirihara, Masayuki; Kimura, Yoshikazu
• Is Part Of: Tetrahedron. Volume 72:Issue 22(2016)
• Page Start: 2818
• Page End: 2827
• Publication Date: 2016-06-02
• Subjects: TEMPO (2, 2, 6, 6-tetramethylpiperidine 1-oxyl) -- 1-Me-AZADO (1-methyl-2-azaadamantane N- oxyl) -- Sodium hypochlorite pentahydrate (NaOCl·5H2O) crystals -- l-Menthol -- Oxidation -- Aldehyde -- Ketone; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2016.03.064
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: The novel oxidant of sodium hypochlorite pentahydrate (NaOCl·5H2 O), which is now available for industrial and laboratory use has several advantageous properties. The crystalline material has 44% of NaOCl, contains minimal sodium hydroxide and sodium chloride, and the aqueous solution indicates pH 11–12. Herein, NaOCl·5H2 O crystals are examined for use as an oxidant for primary and secondary alcohols, with or without nitroxyl radicals, in the presence or absence of phase-transfer catalysts. The pentahydrate crystals alone (without nitroxyl radicals) demonstrate a powerful oxidizing ability, converting secondary alcohols to the corresponding ketones. In the presence of TEMPO (2, 2, 6, 6-tetramethylpiperidine 1-oxyl) or 1-Me-AZADO (1-methyl-2-azaadamantane N -oxy radical), sterically hindered secondary alcohols are oxidized without pH adjustment. A proposed mechanism for the oxidation is discussed. Graphical abstract: