Buy asset from ROTH IRA to ROTH 401k. Prohibited transaction?

[Mike S.]

While it is not possible to roll over from a ROTH IRA to a ROTH 401(k), would it be possible to have the ROTH 401(k) buy an asset from a ROTH IRA? Would it be a prohibited transaction?

I have some investments in a syndication that would trigger important UDFI taxes at final redemption. I would like to be able to transfer them to a ROTH 401(k) to avoid this tax. Initially when the investment was bough I didn't have enough money in the ROTH 401(k) and had to use the ROTH IRA instead. Now that I have enough cash of in the ROTH 401(k) I would like to buy it back from the ROTH IRA.