Ironically, war has produced many useful inventions.

Literal

Ironically war [subject-が] many useful inventions [object-を] produced.

皮肉なことに means 'ironically' — 皮肉 means 'irony/sarcasm,' こと nominalizes, に makes it adverbial. 生み出す means 'to produce, give birth to' — a compound verb.