Chain extension with tert‐butyl lithioacetate

Iodides containing methylene-interrupted triple or double bonds can be chain-extended in 45-73% yield by reaction with tert-butyl lithioacetate in THF/HMPT at −35°C and subsequent acid-catalyzed thermolysis at 100°C. Alkyl and allyl bromides or iodides give acids in yields of 60 to 89%. In some cases, minor amounts of methyl ketones were found. Alkyl chlorides and alkyl methane-, benzene- or p-toluenesulphonates are not suitable.