In this report, two distinctive intramolecular cyclizations of o-propargyloxy diketopiperazines (achieved from a one-pot Ugi post-transformation) is achieved via a copper(I)-catalyzed intramolecular reaction of azomethine ylide and alkyne moiety. The presence of internal alkyne in the starting materials directed the reaction towards through [3 + 2]-cycloaddition, while terminal alkyne led to a spirocyclization reaction between azomethine ylide and terminal unsaturated CÀ C bond. This method offering an opportunity for the synthesis of challenging Diazabicyclics and Spiro-Diketopiperazinochromanes in high yields with exclusive diastereoselectivity.
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