the european part of it.

for napoleon, it was the 1812 summer offensive. napoleon thought he could invade and force russian surrender in months. he didn't even pack winter supplies. he made it all the way to moscow that fall only to find the russians had set it ablaze. he retreated within a month and limped back through the snow with 1/10th of his unprepared army.

in WWII, hitler famously repeated this blunder in the summer of 1941 in launching operation barbarossa, breaking a peace the germans held with the soviets (molotov-ribbentrop pact), once again thinking they could take moscow before the winter. the germans got as close as seeing "the spires of the kremlin" that fall and winter, but it was ultimately hitler's downfall and the end for about 30 million troops and civilians.

both of those invasions happened in europe, not asia.

there is an asian part of russia, but that's east of the ural mountains which are about 800 miles east of moscow (and a tiny bit on the south slopes of the caucuses, but that's not important right now).

neither napoleon nor hitler invaded iran or anywhere near it. in 1941, the germans encouraged a coup in iraq and installed a puppet government to get them more access to oil. the brits, also liking oil, put an end to that in like a month with very few casualties.