Preparation of Building Blocks for Iterative Suzuki-Miyaura Reactions via Direct Bromination of Aryl Boronic Acids: One-Pot Total Syntheses of Dictyoterphenyls A and B

A highly efficient method for the preparation of 4-alkoxy-3-bromophenyl boronic acid N-methyliminodiacetic acid (MIDA) esters as building blocks in iterative Suzuki-Miyaura reactions from the 4-alkoxyphenylboronic acids is described using a boronic acid moiety as a blocking group in bromination reactions. With these MIDA boronates, the total syntheses of dictyoterphenyls A and B were developed in only two separate one-pot operations. Furthermore, we have developed a more practical protocol for the preparation of meta-terphenyl natural products by simply adding the second aryl halide and water to the reaction mixture via the controlled release technique. (Figure presented.).