Exception to 5-year rule for certain amounts payable over life of beneficiary .—

any portion of the employee’s interest is payable to (or for the benefit of) a designated beneficiary,

such portion will be distributed (in accordance with regulations) over the life of such designated beneficiary (or over a period not extending beyond the life expectancy of such beneficiary), and

such distributions begin not later than 1 year after the date of the employee’s death or such later date as the Secretary may by regulations prescribe,