Rh-Catalyzed [3+2] Annulation of Cyclic Ketimines and Alkynyl Chloride: A Strategy for Accessing Unsymmetrically Substituted and Highly Functionalizable Indenes

Alkynyl chlorides
were found to be extraordinarily novel electrophiles,
which could afford a single regioisomer of the [3+2] annulation adducts
with cyclic ketimines by rhodium catalysis. The alkenyl chloride moiety
in the products provided a valuable functional handle for further
diverse transformations. Therefore, this research provided not only
a synthetic protocol for accessing unsymmetrically substituted indenyl
amines but also a highly divergent solution for decorating the substituting
group by postmanipulation of the chloride.