Silver-Catalyzed Tandem Cyclization for Syntheses of Azaoxa- and Diazaspirocycles

1-Azaspirocycles are important structures present in many drugs and natural products. This paper describes the silver-catalyzed tandem cyclization strategy, which provides atom-economical access to various azaoxa- and diazaspirocycles from alkynes containing two appended oxygen- and nitrogen-based nucleophiles. Intramolecular attack of the pendant nucleophile on the in situ-generated iminium intermediate is the key to the success of this transformation.