Is it appropriate to "shop" through high-impact journals before sending the paper to more specialized journals? I have recently finished writing my first paper for my PhD study. I believe I have made some discoveries, but by comparing my manuscript to previous work, I think the advance is not very big and the work should be published on specialized journal in my field. 

However, my supervisor does not agree with me and he really wants to try publishing it on a high-impact journal. I have talked multiple times with him, listing the novelty and limitations of my study, as well as the journals that previous work mostly published on. But he put my suggested journals on the last positions of his list, saying that he hope my work should be read by more people. Other students in my lab told me that they have met similar scenarios before.

Up to now we have tried Nature Communications, eLife and Current Biology, all being rejected without full scale peer-review. The review editors in one journal point out some limitations in my study, and we addressed them before submitting again; the other two turned my manuscript down without pointing specific problems.

My questions are:


Is it appropriate to "shop" through high-impact journals (all getting desk rejections) before submitting to specialized journals, with modifications made if specific suggestions have been received?
How can I talk to my mentor to reduce publication time for my future papers?
Judging the value of work is subjective, and can differ significantly between different researchers.

There is not harm in trying high-impact journals if some experienced people (like your mentor) consider it worth-while. But if you tried three different journals and get more or less immediate rejections, you should probably aim lower. Otherwise you just waste time in waiting for another five rejections (and you also waste the time of the editors/reviewers). 

Maybe, after three rejections, you can discuss this topic with your mentor again, mentioning that you don't want to wait another three years for your paper to be published.