Lead salts decarboxylative halogenation

Malonic acid, ethyl malonate, and their monoalkyl derivatives can be readily halogenated in ether solution subsequent decarboxylation leads to the corresponding a-halogenated acetic acid in 55-80% yield. The reaction of the potassium salts of monoethyl alkylmalonates with bromine provides the a-bromo esters directly, although the yields ate relatively low. ... 

---