Nope. If you do this, Germany will have a big stack of units in Italian East Poland by R3 that is too big for Russia to take it back. Russia can declare war on Germany once Italy has declared war on Russia, but as of G3 they are not yet at war so Germany gets the wheat NO even with their troops in Italian East Poland.
The Russian Murmansk NO says:
When the Soviet Union Is at War in Europe:
5 IPCs if the convoy in sea zone 125 is free of Axis warships, Archangel is controlled by the Soviet Union, and there are no units belonging to other Allied powers present in any territories originally controlled by the Soviet Union.
And the German wheat NO says:
When Germany Is Not at War with the Soviet Union:
5 IPCs representing wheat and oil from the Soviet Union.
So if Russia is at war in Europe they don’t get the Murmansk NO if there is an axis warship in z125. Germany on the other hand can collect the wheat NO as long as its not at war with Russia even if it has units in an Italian territory that was originally soviet. Russia cannot simply refuse to declare war on Germany R3 just to get the Murmansk NO because a German sub in z125 is still an Axis sub.