An efficient synthesis of the tricyclic spiroindolinone fragment 3 of the marine alkaloid citrinadin A (4) has been achieved. The approach features a new asymmetric oxidative rearrangement of an indole to an oxindole using a chiral auxiliary on the indole nitrogen to achieve facial selectivity. This DMDO-mediated transformation proceeds in moderate yield and high diastereoselectivity and allows for efficient construction of the two adjacent quaternary centers present in 4. Efforts toward the fragment coupling of tricyclic spiroindolinone 3 with a 2,4,6-trisubstituted piperidine coupling partner and subsequent elaboration toward the natural product will be presented.