You will deduct it like any normal HOA fee paid in the year you paid it.
A part of your reg HOA fees is applied to the reserves normally and as such deductible annually. The fact that you had a shortfall you had to come up with all at once doesn't change that fact. And I think the HOA needs to take a hard look as to why the reserves where not sufficient to handle at least the foreseeable repairs like at least the roof and why no one noticed/anticipated the other needed repairs earlier so they could be saved for... lack of a healthy reserve may be signs of a deeper issue.
