Here's an excellent article, with copious references, tracing the history of what we now know as the metal-catalyzed coupling field. Victor Snieckus of Queen's University, Thomas Colacot (Johnson Matthey) and co-authors go back to the Wurtz and Glaser reactions of the 1850s and 60s, up through the Ullmann reaction (1891, and still very much with us) and Kharasch and Cadiot-Chodkiewicz couplings (1940s) before breaking into the world of palladium with the Wacker oxidation.

Along the way, one learns that the discoverer of palladium (Wollaston) could never interest anyone in the metal, and almost all of it that he'd extracted was still sitting on the shelf, unsold, at his death. Time vindicated him, and how - it's now perhaps the most essential catalytic metal in the world. The late 1960s were a turning point:

Entry of Richard Heck: Following post-doctoral studies, Heck accepted a position at Hercules Powder Co where he was afforded freedom that is seldom experienced by the modern industrial chemist. Briefed with the task of “doing something with transition metals,” Heck investigated the chemistry of cobalt carbonyl complexes. Although this work generated many interesting observations, finding profitable applications for his research proved difficult. Inspired by his colleague Pat Henry's work on the Wacker oxidation, Heck's attention turned in the direction of arylpalladium chemistry.

He tried Wacker-type conditions with other reagents around to try to intercept the palladium intermediate, and organomercurys obliged with an immediate reaction. The story from there is a trip through a good swath of the periodic table, and the development of an awful lot of knowledge and expertise in metal complexes. Enter then Mizoroki, Kumada, Sonogashira, Negishi, Stille, Suzuki and many others. It's a long, complex, story, but this paper should serve as the definitive overview, and an excellent look at how chemistry (and science in general) go about discovering and developing things.