I want to start by mentioning how courageous it is of you to share this question-I know that there are many attorneys who will be able to relate to what you are dealing with and will be comforted by seeing that they are not the only ones facing this type of situation. It sounds like you are going through a very difficult situation, but you are certainly not alone.
Dealing with a difficult attorney/partner who is in a position of power (in terms of seniority, etc.) is one of the most common challenges junior (and more senior) attorneys face. Given the stresses and inherent pressures of practicing law, combined with the intense personalities of many attorneys, it is not surprising that some attorneys-wrongly-take their stresses and frustrations out on people who have less power and happen to be in their lines of fire.
Oftentimes in a large law firm, many of the difficult partners bring in a lot of business and feel that they add an amount of financial value to the firm that somehow justifies their behavior. Unfortunately, while many other partners in the firm may be aware of these particularly difficult partners, they will look the other way because they don't want to create conflict and the partners with the big books of business often wield more power.
So what do you do in this situation? First off, staying where you are and accepting the status quo will continue to take a toll on you emotionally, and probably physically, and will continue to affect your performance. If you are ridden with anxiety each time you need to speak with one of these partners, you are probably focusing your energy on how to emotionally protect yourself from being criticized by them rather than on doing the best job you can on the work itself. This is one of the ways in which a partner's difficult personality adversely impacts the quality of a firm's legal work.
I'd strongly suggest exploring how you can start working with other people in your practice group or firm. You may not be able to remove yourself entirely from this situation, but you could try to transition away from these partners and fill your plate with new work from other partners.
If your practice area or firm has somebody who coordinates work for junior associates, you should speak to that person. You should be careful not to "trash" the partners (no matter how upset or resentful you may feel), but respectfully ask whether you can broaden your exposure to other partners or projects. (They'll be able to read between the lines and get the point.)
If there is no person who coordinates the assignment of work to junior associates, you should make efforts to meet more partners and let them know about your willingness to help out with any existing or potential project that comes in. Better yet, if you have a mentor or friend who is more senior than you, consider speaking to this person in confidence about your predicament. You will likely benefit from the advice of somebody who has more institutional knowledge about the partners and may have concrete suggestions on how you can best navigate this situation.
You have two things in your favor: (1) you have been told that you do good work and (2) these partners are "notoriously difficult" to work with. Thus, it should not come as a surprise that you would like to remove yourself from their work. Odds are many associates have been in your same situation with the same partners.
If you suffer silently and "suck it up," the firm could assume that you don't mind working for these partners. Without any indication otherwise, they could be thinking, "Phew! We finally found somebody who is able to tolerate them." And if you are performing well (which you are), the firm will not want to lose you because the cost of replacing an associate is very high.
Because you are a first-year associate, it will be much easier to lateral to another firm once you have been at this firm for at least one full year. Even if you have a good reason for wanting to leave, firms see a yellow flag when somebody is looking to leave a firm during the first year of employment.
People certainly are able to switch firms with less than one year of experience, but it's more difficult and there's more explaining that needs to be done. Thus, to the extent you can take action to start alleviating these uncomfortable working conditions, I'd start right now. If you try-in earnest-to remove yourself from working with these partners but are unable to transition at all after several months, you will be in a better position to consider a lateral move. It is usually best to exhaust all possible solutions at your current firm before seeking employment at a new firm.
Lastly, I would like you to take a look at an article from the Legal Times on "BAS," which is a tongue-in-cheek acronym for "battered attorney syndrome." You may find this article helpful as well. Here's a link to the PDF:
I sincerely hope that your situation improves. Please write back in a few months and let me know how your strategy is playing out-maybe it will be worth providing the readers with an update on what you did and how effective your strategy was.