A 777-200LR, built in 2009, has been retired by Air India according to photos here: Exclusive photos: Air India cannibalises 777 named Maharashtra at Mumbai’s Shivaji airport.
While the rumors mentioned on the website suggest it sustained hidden damage during a heavy landing, it's still notable that a modern 777 less than five years old is being cannibalized. However, this may speak more of the market for the 777-200LR rather than any financial issues with Air India. While the 777 is undoubtedly a popular aircraft these days, it's the 777-300ER that is the star of the show rather than the smaller 777-200LR. According to Aviation Week Intelligence Network's Fleet database, 469 777-300ERs have been delivered with another 253 on order. Compare this with 57 777-200LR deliveries so far and just two remaining on order (not counting the 777F). It's possible that the value of the 777-200LR is such that some repairs are simply not economical, if that's the case with this 777.
So is this the youngest jet airliner to be parted out? Not quite. A318s previously operated by Frontier Airlines were retired young, with the youngest getting parted out at just 27 months of age. Some aircraft have been retired even earlier, although one could argue it was due to special circumstances. BAE axed its RJX program in 2002 after only one RJX85 and two RJX100s were built. Because it would not make financial sense for anyone to support such a small orphan fleet, none were delivered and all three were retired with the youngest one having first flown just 14 days earlier. Then there's Fairchild Dornier which was forced to retire its two new 728s due to bankruptcy. Neither one had flown, but the prototype had already been ceremoniously rolled out in full Fairchild Dornier colors, just months away from its first flight.
Despite these notable early retirements, a trend toward "disposable" aircraft has not emerged.