Recent Strategies in Nickel-Catalyzed C–H Bond Functionalization for Nitrogen-Containing Heterocycles
Round 1
Reviewer 1 Report
In this work, the author provided recent advances of nickel-catalyzed C‒H functionalization in heterocycle synthesis. Indeed, Ni-catalyzed reactions are received significant attention in recent days. This review is well written and sound for publications. However I am missing some information, overview of the type of C-H activation and heterocycles in a table, a nice future scope. The future scope should be focus on the realistic scenario considering the price, scale and scope. A suitable comparison with other Pd-, Co- and Mn- based catalyst should be beneficial for the future reader.
Overall the quality of this review is good and should publish after this minor modifications.
Thank you
Author Response
Please see the attached file.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this manuscript, the author introduces the recent progress in the field of nickel-catalyzed N-heterocycle synthesis via C-H functionalization. The overall quality of this manuscript is very good with strong logical description and clear drawing, and the references are representative and appropriate. Therefore, this reviewer in favor of publication after some minor issues are addressed.
1. Scheme 1B is confusing, the current description indicated that starting material 1 was obtained after the reductive elimination of Int. 1B?
2. Line 116, an explanation of abbreviation “CMD” (Concerted metalation deprotonation) should be given in the text.
3. All of the Valence state of Ni of intermediates in catalytic cycle should be indicated, such as in Scheme 7, 13b, 16.
4. Scheme 8, one of the “R” group in structure “20-21” should be “R1”
5. There are two “Scheme 16” in line 313 and 316, and the current “Scheme 17” should be “Scheme 18”, which should be revised.
6. Line 347, the title of current Scheme 17, the description of “Ni(II)-catalyzed…” is inappropriate, because the real catalyst in this catalytic cycle is Ni(0). I consider using expression “Ni-catalyzed…”, like the original publication (OL, 2020, 22, 3810) should be suitable here.
Author Response
Please see the attached file.
Author Response File: Author Response.pdf
Reviewer 3 Report
1. Please change the title to “Recent strategies in nickel-catalyzed C‒H bond functionalization for nitrogen-containing heterocycles”.
2. What does it exactly mean? “in last decade or so.” Please write the exact years!
3. Recently, an important review article (about C-H functionalization for the synthesis of indazole as a significant scaffold in organic chemistry) has been published in Molecules. Please check it and cite it. This review article has been published very recently and is completely relevant to your review article. https://www.mdpi.com/1420-3049/27/15/4942
4. This review is very brief. Please add more articles if there are.
5. The schemes are very large. It should be a little smaller.
6. Please change this sentence to a better one “they are also classified based on their ring size into three, four, five, six, seven-membered N-heterocycles and so on.” For example, “they are mainly classified based on their ring size into three, four, five, six, seven-membered N-heterocycles.”
7. Please change this sentence to a better one “Nitrogen-containing heterocyclic compounds have unique biological activity, low toxicity, as well as high internal absorption, rendering them as potent medicines and bioactive compounds [1-7].” For example, “Nitrogen-containing heterocyclic compounds have unique biological activity, low toxicity, and high internal absorption, rendering them potent medicines and bioactive compounds [1-7].
8. Please change the “synthesizing” to “synthesize” in this sentence “So far, pursuing means to efficiently synthesizing N-heterocycles has been a key target for organic and pharmaceutical chemists.”
9. Please compare the significance of this review with previously published ones. Very important to explain it clearly.
10. This sentence needs some references. “Furthermore, they are also classified based on their ring size into three, four, five, six, seven-membered N-heterocycles and so on.” I suggest some references for you.
This reference is for four and five-membered N-heterocycles.
https://onlinelibrary.wiley.com/doi/abs/10.1002/jhet.3491
https://www.ingentaconnect.com/content/ben/mrmc/2021/00000021/00000005/art00003
These two references are for five-membered N-heterocycles.
https://pubs.rsc.org/en/content/articlehtml/2020/ra/d0ra05150k
https://www.beilstein-journals.org/bjoc/articles/17/114
The authors also can find some for six and seven-membered ones.
Author Response
Please see the attached file.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
The article can be accepted.
