As long as the distributions to charities come from income and are specified in the trust document, they are deductible. I cannot imagine why the trustee would want to pay the taxes for the beneficiaries, who may end up receiving a lot less than if they paid the taxes at their own rates. The only way to do it would be to make no distributions, pay the income tax, and then pay the beneficiaries the next year. Does the trustee understand his or her fiduciary duties?