Scope and Limitations of the Palladium-Catalyzed Cross-Coupling Reaction of in situ Generated Organoboranes with Aryl and Vinyl Halides

✍ Scribed by Maddaford, Shawn P.; Keay, Brian A.

• Book ID: 111861373
• Publisher: American Chemical Society
• Year: 1994
• Tongue: English
• Weight: 342 KB
• Volume: 59
• Category: Article
• ISSN: 0022-3263
• DOI: 10.1021/jo00101a001

✦ Synopsis

The in situ palladium(0)-catalyzed Suzuki reaction is shown to be an efficient method for the crosscoupling of aryl-, furyl-, primary, and benzylic boranes with aryl or vinyl bromides and iodides without the isolation of the organoboronic acid or the addition of any external base.

In our previous attempts to apply the Stille-type crosscoupling of (tri-n-butylstanny1)furan 2 with aryl bromides, we observed low yields of cross-coupled products ('50% yields), and no reaction was observed with vinyl halides, 2-bromopyridine, or 1-bromo-2-methoxybenzene (Scheme 1).l In contrast to the Stille couplings of 2, the corresponding 4-lithiofuran 1, when treated with trimethoxyborane (B(OMe)3) followed by a palladium catalyst and water (no external base), cleanly underwent an in situ Suzuki cross coupling with a variety of aryl and vinyl halides and triflates.2 Since previous successful Suzuki cross-couplings of vinyl-: and arylboronic5