Ligand exchange reaction of sulfoxides in organic synthesis: A versatile procedure for one-carbon homologation of methylesters to esters, thioesters, carboxylic acids and amides

✍ Scribed by Tsuyoshi Satoh; Hideaki Unno; Yasuhiro Mizu; Yasumasa Hayashi

• Publisher: Elsevier Science
• Year: 1997
• Tongue: French
• Weight: 624 KB
• Volume: 53
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(97)00478-x

✦ Synopsis

A novel two-step procedure for one-carbon homologation of methylesters to esters, thioesters, carboxylic acids and amides is described. Methylesters are reacted with lithium carbanion of chloromethyl phenyl sulfoxide to give a-chloro a-sulfinyl ketones in 70 to 90% yields. Potassium enolate of the a-chloro a-sulfinyl ketone was treated with tert-butyllithium at -78 °C to give alkynolate via alkylidene carbenoid. This intermediate was treated with alcohols, thioles, 5% aqueous NaOH, and amine hydrochlorides to afford one-carbon homologated esters, thioesters, carboxylic acids and amides, respectively, in good to excellent yields.