Remote <i>meta</i> -C–H Functionalization of Baylis–Hillman Adducts

The Baylis-Hillman (BH) adducts have become very useful building blocks in a variety of organic syntheses. Herein, an unprecedented, challenging, and distal C-H activation of BH adducts via a directing group strategy (DG) has been disclosed for the first time. This novel method not only is the first C-H activation of BH adducts but also paves the way for solving the long-standing problem of decorating the aryl part of the BH adducts with various functionalities in a selective manner. We have also developed a selective mono- and dialkenylation of BH adducts by tuning the reaction conditions. This new protocol has a wide substrate scope, simple reaction conditions, excellent yields, excellent <i>meta</i>-selectivity, and very good functional group tolerance. Late-stage modification of drugs and bioactive molecules, as well as the removal of DG, has also been achieved.