Directing group assisted para -selective C-H alkynylation of unbiased arenes enabled by rhodium catalysis.

Regioselective C-H alkynylation of arenes via C-H activation is challenging yet a highly desirable transformation. In this regard, directing group assisted C(sp 2 )-H alkynylation of arenes offers a unique opportunity to ensure precise regioselectivity. While the existing methods are mainly centered around ortho -C-H alkynylation and a few for meta -C-H alkynylation, the DG-assisted para -selective C-H alkynylation is yet to be reported. Herein we disclose the first report on Rh-catalyzed para -C-H alkynylation of sterically and electronically unbiased arenes. The para -selectivity is achieved with the assistance of a cyano-based directing template and the selectivity remained unaltered irrespective of the steric and electronic influence of the substituents. The post-synthetic modification of synthesized para -alkynylated arenes is also demonstrated. The mechanistic intricacies of the developed protocol are elucidated through experimental and computational studies.