Herein, we describe a base‐promoted successive (3 + 2) annulation/aromatization reaction of hex‐5‐en‐2‐ynoates with (iso)quinolin‐2‐ium‐2‐yl(tosyl)amides, in which hex‐5‐en‐2‐ynoates act as a novel and regioselectively distinct C2 synthon in this process. The use of β‐ and γ ‐carbons of the substrates for CC bond formation is distinct from the substrate‐controlled divergent reactivity reported previously. The reaction provides an efficient route to highly functionalized pyrazolo5,1‐a(iso)quinolines, delivering moderate to good yields with exclusive regioselectivity under mild conditions. The products can be further functionalized through reduction or hydrogenation, indicating their potential applications.
Zhang et al. (Mon,) studied this question.