These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.

Imine as a Linchpin Approach for Distal C(sp2)–H Functionalization

submitted on 06.01.2020 and posted on 07.01.2020 by Sukdev Bag, Sadhan Jana, Sukumar Pradhan, Suman Bhowmick, Nupur Goswami, Soumya Kumar Sinha, Debabrata Maiti

Despite the widespread applications of C–H functionalization, controlling site selectivity remains a significant challenge. Covalently attached directing group (DG) served as an ancillary ligand to ensure proximal ortho-, distal meta- and para-C-H functionalization over the last two decades. These covalently linked DGs necessitate two extra steps for a single C–H functionalization: introduction of DG prior to C–H activation and removal of DG post-functionalization. We introduce here a transient directing group for distal C(sp2)-H functionalization via reversible imine formation. By overruling facile proximal C-H bond activation by imine-N atom, a suitably designed pyrimidine-based transient directing group (TDG) successfully delivered selective distal C-C bond formation. Application of this transient directing group strategy for streamlining the synthesis of complex organic molecules without any necessary pre-functionalization at the distal position has been explored.


SERB India (CRG/2018/003951)


Email Address of Submitting Author


Indian Institute of Technology Bombay



ORCID For Submitting Author


Declaration of Conflict of Interest

The authors declare the following competing financial interest(s): A patent application is filed based on the work described in this manuscript


Logo branding