[noun] + に至って [noun] + に至り
Note: The noun typically represents a critical stage, situation, or event.
The grammar pattern に至って / に至り expresses the idea that a situation has finally reached a critical point or stage, and only then does something happen or become apparent. It carries the nuance that things had been progressing for some time, but it was not until reaching this particular stage that a reaction, realization, or action finally occurred. It often implies that the response came too late or that the situation had to become quite serious before something was done.
The verb いたる至る (いたる) means "to reach" or "to arrive at," so に至って literally means "upon reaching (that point)." The form にいたり至り is a more formal/written conjunctive form (連用形) used in the same way.
に至って is typically attached to a noun or noun phrase that represents a stage, situation, or turning point.
This pattern frequently appears with words like ようやく, はじめて初めて, and やっと, reinforcing the sense that the action or realization should have come sooner.
Be careful not to confuse this with related expressions: