Concise Synthesis of Cyctetryptomycin A and B Enabled by Zr-Catalyzed Dimerization.

A concise synthetic strategy utilizing a Zr catalyst for the construction of cyctetryptomycin A and B is reported. Cyctetryptomycin A and B are recently isolated, complex tetrameric natural products for which total synthesis has not been previously reported. This study presents a practical approach for the construction of two consecutive quaternary carbon centers with a Zr catalyst.

Modular, Scalable Total Synthesis of Lapparbin with a Noncanonical Biaryl Linkage.

We report the development of a novel synthetic approach for the highly strained atrop-Tyr C-6-to-Trp N-1' linkage, which can be executed on a decagram scale using a modular strategy involving palladium-catalyzed C-H arylation followed by Larock macrocyclization. The first total synthesis of lapparbin (1) was achieved by applying this synthetic strategy. Furthermore, the modular synthesis utilizing C-H arylation and Larock macrocyclization, discovered in the total synthesis of lapparbin (1), was demonstrated to be applicable to various arbitrary biaryl linkages, including non-natural types.