D-sharp minor
The most famous work in this key is Scriabin's famous Etude Op. 8, No. 12. Russian composer Lyapunov must also have liked the key because he wrote the second etude of his Op. 11 set in the key, and also fifteen years later his Variations on a Russian Theme, Op. 49.  His early Piano Concerto No. 1, Op. 4 was also in the enharmonic key of E-flat minor.