Synthesis of Unnatural Amino Acids via Ni/Ag Electrocatalytic Cross-Coupling.

A simple protocol is outlined herein for rapid access to enantiopure unnatural amino acids (UAAs) from trivial glutamate and aspartate precursors. The method relies on Ag/Ni-electrocatalytic decarboxylative coupling and can be rapidly conducted in parallel (24 reactions at a time) to ascertain coupling viability followed by scale-up for the generation of useful quantities of UAAs for exploratory studies.

Solvent-dependent chemoselectivity in ruthenium-catalyzed cyclization of iodoalkyne-epoxide functionalities.

[reaction: see text] Treatment of 1-(2'-iodoethynylphenyl)-2-propyloxirane (3) with TpRuPPh(3)(CH(3)CN)(2)PF(6) catalyst (10 mol %) produced 1-iodo-2-naphthol (3a) exclusively in DMF, but gave 2-iodobenzo[d]oxepin (3b) efficiently in benzene. Such a solvent-dependent chemoselectivity suggests a solution equilibrium between ruthenium-pi-iodoalkyne and ruthenium-2-iodovinylidene intermediates.