Iterative Suzuki-cross

The efficient synthesis of a potent topoisomerase I poison terbenzimidazole was developed in the laboratory of P.J. Smith. The desired aryl-aryl bonds were created via iterative Suzuki-cross couplings. The arylboronic ester was derived from 1-benzyl-5-iodo-1/-/-benzimidazole using the Miyaura boration. 

The MIDA-protected boronate esters developed by Burke and coworkers allow iterative Suzuki cross coupling reactions under mild conditions to give polyenes [64,65]. The MIDA-protected boronate esters are stable and easily handled, and deprotection occurs readily at room temperature under mild basic conditions to provide the corresponding boronic acids. 

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