The application of PhICl2/NH4SCN and PhICl2/KSeCN reagent systems to the synthesis of the biologically active S/SeCN-containing isocoumarins via a process involving thio/selenocyanation, enabled by thio/selenocyanogen chloride generated in situ, followed with an intramolecular lactonization was realized. Gram-scale synthesis, further derivatization to access C4 thio/selenocyanated Xyridin A and anti-tumor activities of the obtained products highlight the potential use of this method.

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Synthetic methods of unnatural α-amino acids have always been the focus of extensive research due to their significant bioactivities. However, convenient transition-metal-free catalyzed methods are still in demand. Herein, we report a novel strategy for the construction of an unnatural α-amino acid skeleton via intramolecular rearrangement of carbamates, which are readily available from amines and their common protecting groups. This rearrangement could afford a variety of amino ester products in up to 98% yield, even in gram-scale reaction. The reaction mechanism was studied in detail through experiments and theoretical calculations. The complex-induced proximity effect (CIPE) from the 2-pyridyl group is shown to be indispensable for this transformation.