Osmotolerant yeast is specifically designed for high-sugar doughs and is the best choice for sweet breads, brioche, donuts, pastries, and other enriched baked goods. Unlike regular yeast, osmotolerant yeast can withstand the water-absorbing effects of sugar, which otherwise leaves yeast "thirsty" and dormant.
Of course, when I ordered some from Amazon, it came to me dead, and I threw it out. I haven't tried it again; I just add in a longer rise time to my schedule.