Without a painful grind? No. However I find it easy to get legendaries from the cryptarch by ranking up with him. Try gathering lots of blue engrams through ROC strikes and the daily mission. You should level up your cryptarch rank at least once in at most two hours. Another way to obtain legendaries is through ranking up with vanguard and crucible. Just gather as many bounties as you can and choose a journey (PvP or pve). Not only will you gain reputation to rank up (so you can get legendary stuff from postmaster) but you will also get marks to spend at e quartermasters.