Alkali Barbier reaction

Grignard reagents usually give poorer yields than do the alkali metal reagents, but some reactions give good yields under Barbier conditions with ultrasonic assistance (Equation (56)).7... 

In 1991, Li and Chan reported the use of indium to mediate Barbier-Grignard-type reactions in water.12 The work was designed on the basis of the first ionisation potentials of different elements, in which indium has the lowest first ionisation potential relative to the other metallic elements near it in the periodic table. On the other hand, indium metal is not sensitive to boiling water or alkali and does not form oxides readily in air. Such special properties of indium indicate that it is perhaps a promising metal for aqueous Barbier-Grignard-type reactions. Indeed, it appears that indium is the most reactive and... 

---