Adjust salt (in mushrooms)
Consider looking at the situation from a different perspective. Canned mushrooms are an inferior substitute for fresh mushrooms. Whatever benefit they add to the recipe, would likely be improved by using fresh mushrooms.

Instead of attempting to pre-process your fresh mushrooms to make them more like canned mushrooms, why not simply adjust your recipe to use the fresh mushrooms directly?

Without the details of your recipe, it's impossible to know exactly what adjustments are needed — though, you might very well be able to substitute fresh mushrooms directly, with no pre-processing other than washing and slicing them.

Keep in mind the following:


Mushrooms cook very quickly. For example, if you are adding them to other sautéed vegetables, add them when the other vegetables are nearly cooked.
Fresh mushrooms contain a lot of moisture, which is released as they cook. This will add flavor to a sauce, but you may need to lengthen the reduction time.
Mushrooms can be eaten raw, though many people prefer them cooked. The longer you cook them, the more the texture changes. Cooked just until tender, mushrooms will be succulent and juicy, with lots of mushroom flavor. When cooked past that point, the mushroom juices are released and the mushrooms will absorb flavors from their companion ingredients.


Your proposal of boiling the mushrooms would just boil away the most of the mushroom flavor. Canned mushrooms add lots of salt, partly as a preservative, but also because the mushrooms are quite tasteless. Changing your recipe to take advantage of having fresh mushrooms will make it healthier and more delicious.