Answer
Expanded possibilities of organic synthesis, particularly involving carbon-carbon bond formation. Grignard's discovery of the Grignard reagents, organometallic compounds formed from alkyl or aryl halides and magnesium metal, revolutionized organic chemistry. These reagents serve as highly reactive nucleophiles, enabling the formation of various carbon-carbon bonds efficiently. Their versatility has found widespread applications in the synthesis of complex organic molecules, natural products, pharmaceuticals, and fine chemicals.