Transformation of ketones and aldehydes to gem-dihalides via hydrazones using copper(II) halides

✍ Scribed by Takeshi Takeda; Rika Sasaki; Satoshi Yamauchi; Tooru Fujiwara

• Book ID: 104207371
• Publisher: Elsevier Science
• Year: 1997
• Tongue: French
• Weight: 621 KB
• Volume: 53
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(96)00981-7

✦ Synopsis

Preparation of gem-dihalides by the oxidation of hydrazones, which were easily prepared by the treatment of ketones and aldehydes with hydmzine hydrate in the presence of molecular sieves 4A. with copper compounds was studied. The treatment of hydmzones with coppert'lt) bromide-lithium tert-butoxide in THF gave the corresponding gem-dibromides in good yields. gem-Dichlorides were also obtained by the similar reaction of hydmzones using copper(I1) chloride-lithium rerr-butoxide as an oxidizing agent. Furthermore it was found that the same transformations were conveniently achieved by the use of copper(I1) halides-ttiethylamine in methanol.