Catalytic cycloisomerization-initiated cascade cyclizations of terminal alkynes have received tremendous interest, and been widely used in the facile synthesis of adiverse arrayof valuable complex heterocycles.H owever,t hese tandem reactions have been mostly limited to noble-metal catalysis,and are initiated by an exo-cyclization pathway. Reported herein is an unprecedented copper-catalyzed endo-cyclization-initiated tandem reaction of indolyl homopropargyl amides,w here copper catalyzesb oth the hydroamination and Friedel-Crafts alkylation process.This method allows the practical and atomeconomical synthesis of valuable bridged aza-[n.2.1] skeletons (n = 3-6) with wide substrate scope,and excellent diastereoselectivity and enantioselectivity by ac hirality-transfer strategy. Moreover,t he mechanistic rationale for this novel cascade cyclization is also strongly supported by control experiments, and is distinctively different from the related gold catalysis.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

A novel Brønsted acid-catalyzed reaction of alkynyl thioethers with o-hydroxybenzyl alcohols via an unexpected formal [4 + 2] annulation has been developed. This metal-free protocol leads to the facile and practical synthesis of valuable polysubstituted 2H-chromenes in mostly good to excellent yields under mild reaction conditions and features a wide substrate scope and excellent functional group tolerance.Letter pubs.acs.org/OrgLett

A metal-free intramolecular tandem sequence involving alkoxylation, Claisen rearrangement and lactone expansion has been achieved.

A metal-free intramolecular alkoxylation-initiated cascade cyclization of allyl ether-tethered ynamides has been developed, leading to functionalized 3-isochromanones in high yields.

Catalytic cycloisomerization-initiated cascade cyclizations of terminal alkynes have received tremendous interest, and been widely used in the facile synthesis of adiverse arrayof valuable complex heterocycles.H owever,t hese tandem reactions have been mostly limited to noble-metal catalysis,and are initiated by an exo-cyclization pathway. Reported herein is an unprecedented copper-catalyzed endo-cyclization-initiated tandem reaction of indolyl homopropargyl amides,w here copper catalyzesb oth the hydroamination and Friedel-Crafts alkylation process.This method allows the practical and atomeconomical synthesis of valuable bridged aza-[n.2.1] skeletons (n = 3-6) with wide substrate scope,and excellent diastereoselectivity and enantioselectivity by ac hirality-transfer strategy. Moreover,t he mechanistic rationale for this novel cascade cyclization is also strongly supported by control experiments, and is distinctively different from the related gold catalysis.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.