The selective functionalization of C–H bonds is an extremely important topic in present-day organic synthesis, as it utilizes the most abundant portion of a molecule as a tool for synthetic manipulations. Despite the great progress over the past decade, the major limitation remains the use of an equivalent amount of a directing group to generate the product. The utilization of a native carboxylate group for the same purpose has come up as a better alternative to perform C–H activation, as no exogenous directing group is required to perform the reaction. In this Perspective, we intend to provide a broader picture of transformations that have been carried out by assistance from the carboxylate group and could be applied routinely in the synthesis of complex molecules. The intact carboxylic group in the substrate could be further transformed into different functional moieties, which increases the diversity of such reactions. Extensive coverage of the topic of carboxylate-aided functionalizations of organic molecules without decarboxylation is expected to make this Perspective unique and extremely beneficial to researchers in academia and industry.

In the realm of metallaphotocatalytic C-H activation strategy, the mode of reaction which has been mostly explored is the synergistic effect between a photocatalyst (PC) and a transition metal. In these cases, the energy and redox transfer from the PC to transition metal modulates the oxidation state which brings new mechanistic paradigms in C-H activation and enables prior elusive transformations under milder conditions. Another mode of reactivity occurs via the direct excitation of the transition metal which plays the dual role of light energy harnessing alongside performing the bond breaking and forming. This mode is advantageous because it would not require any exogenous PC, however such reactivity by transition metals is rare in literature. In this context we have developed the rst photo-induced Rh-catalyzed orthoalkynylation under ambient conditions without the requirement of silver salt, PC or any engineered substrate or catalyst. The transformation functions by the speci c cooperative effect of a six-membered rhodacycle which is the photo-responsive species. The catalytic system allows the conjugation of arenes with sp3-rich pharmacophoric fragments. The control experiments as well as the computational studies resolve the mechanistic intricacies for this transformation. An outer sphere electron transfer process from Rh to alkynyl radical is operative for the present photo-induced transformation over the more common oxidative addition or 1,2-migratory insertion pathways. Main TextThe C-H activation strategy gives the provision to streamline the overall process toward a target molecule; thereby empowering the genre of organic synthesis. 1 However, it is a general convention that for a thermally induced C-H activation, a transition metal catalyst is usually accompanied with stoichiometric silver or copper oxidants. 2 This questions the practicality of the method. In order to harness the applicability in true terms it is required to utilize an alternative energy resource that would provide the same outcome but in a sustainable manner. 3 This is where the merger of transition metal catalysis and photocatalysis ts in aptly. The metallaphotocatalysis is an expanding domain in organic synthesis that has revisited and recreated the traditional modes of transition metal catalyzed reactions via unorthodox open-shell mechanisms. 4 The metallaphotocatalysis functions by leveraging on the modulated oxidation state of metal complex involved or generating excited form of intermediate catalytic species; which accounts for the key organometallic step of the transformation. 5 Thus, metallaphotocatalysis provides access to unique reactivity modes through entirely new mechanistic paradigms, that complements the conventional mechanistic approach in the realm of transition metal catalysis. The rede ned mechanistic features enabled by metallaphotocatalysis allow the accomplishment of prior elusive transformations.In general, the metallaphotocatalysis operates by two distinct modes. The rst mode constitutes of the synergistic coo...

In the realm of metallaphotocatalytic C-H activation strategy, the mode of reaction which has been mostly explored is the synergistic effect between a photocatalyst (PC) and a transition metal. In these cases, the energy and redox transfer from the PC to transition metal modulates the oxidation state which brings new mechanistic paradigms in C-H activation and enables prior elusive transformations under milder conditions. Another mode of reactivity occurs via the direct excitation of the transition metal which plays the dual role of light energy harnessing alongside performing the bond breaking and forming. This mode is advantageous because it would not require any exogenous PC, however such reactivity by transition metals is rare in literature. In this context we have developed the rst photo-induced Rh-catalyzed orthoalkynylation under ambient conditions without the requirement of silver salt, PC or any engineered substrate or catalyst. The transformation functions by the speci c cooperative effect of a six-membered rhodacycle which is the photo-responsive species. The catalytic system allows the conjugation of arenes with sp3-rich pharmacophoric fragments. The control experiments as well as the computational studies resolve the mechanistic intricacies for this transformation. An outer sphere electron transfer process from Rh to alkynyl radical is operative for the present photo-induced transformation over the more common oxidative addition or 1,2-migratory insertion pathways. Main TextThe C-H activation strategy gives the provision to streamline the overall process toward a target molecule; thereby empowering the genre of organic synthesis. 1 However, it is a general convention that for a thermally induced C-H activation, a transition metal catalyst is usually accompanied with stoichiometric silver or copper oxidants. 2 This questions the practicality of the method. In order to harness the applicability in true terms it is required to utilize an alternative energy resource that would provide the same outcome but in a sustainable manner. 3 This is where the merger of transition metal catalysis and photocatalysis ts in aptly. The metallaphotocatalysis is an expanding domain in organic synthesis that has revisited and recreated the traditional modes of transition metal catalyzed reactions via unorthodox open-shell mechanisms. 4 The metallaphotocatalysis functions by leveraging on the modulated oxidation state of metal complex involved or generating excited form of intermediate catalytic species; which accounts for the key organometallic step of the transformation. 5 Thus, metallaphotocatalysis provides access to unique reactivity modes through entirely new mechanistic paradigms, that complements the conventional mechanistic approach in the realm of transition metal catalysis. The rede ned mechanistic features enabled by metallaphotocatalysis allow the accomplishment of prior elusive transformations.In general, the metallaphotocatalysis operates by two distinct modes. The rst mode constitutes of the synergistic coo...

Protamine, a polycationic peptide, plays major role in human pharmacotherapy especially as an antidote of heparin to reverse its anticoagulant activity but overdose of protamine (Pr) causes serious health issues....

In the realm of metallaphotocatalytic C-H activation strategy, the mode of reaction which has been mostly explored is the synergistic effect between a photocatalyst (PC) and a transition metal. In these cases, the energy and redox transfer from the PC to transition metal modulates the oxidation state which brings new mechanistic paradigms in C-H activation and enables prior elusive transformations under milder conditions. Another mode of reactivity occurs via the direct excitation of the transition metal which plays the dual role of light energy harnessing alongside performing the bond breaking and forming. This mode is advantageous because it would not require any exogenous PC, however such reactivity by transition metals is rare in literature. In this context we have developed the first photo-induced Rh-catalyzed ortho-alkynylation under ambient conditions without the requirement of silver salt, PC or any engineered substrate or catalyst. The transformation functions by the specific cooperative effect of a six-membered rhodacycle which is the photo-responsive species. The catalytic system allows the conjugation of arenes with sp3-rich pharmacophoric fragments. The control experiments as well as the computational studies resolve the mechanistic intricacies for this transformation. An outer sphere electron transfer process from Rh to alkynyl radical is operative for the present photo-induced transformation over the more common oxidative addition or 1,2-migratory insertion pathways.