Can I amend 2017 itemized return to add charitable donations made in 2018?

Thanks to the new tax law, which we were unaware of until we started our itemized return for 2018, about $3K in charitable donations we made last year are nullified.  We have a lot of stuff around the house that we don't need.  So, to take advantage of the triple-win incentive of giving good stuff to those in need while simplifying our living space and getting a tax break to boot, we've been donating several $K in household items, books, clothes and toys to local charities.  We also make monetary donations to a few non-profits. We've been doing this for the last several years and it's been very mutually beneficial for everyone, accept Uncle Sam.  With the 2018 deductions cap, about 75% of what we gave in 2018 will have no effect on our Federal obligation. If possible, we'd like to file an amendment to claim some or most of the ineffective donations from 2018 on our 2017 itemized return.  As it stands now, we owe a little over $2K.  If we can break even or at least bring that down by half, that would be fantastic.  Thank you.