Walther von Reichenau in Russia

Generalfeldmarschall Walther von Reichenau (Oberbefehlshaber 6. Armee) with his staff officers in the Russian Front during Unternehmen Barbarossa, August 1941 (Wikipedia incorrectly identified the general as Friedrich Paulus, Reichenau's successor as commander of 6. Armee). Reichenau strongly opposed the German invasion of the Soviet Union. Nevertheless, he led his army into the heart of Russia during the summer of 1941. 6. Armee (Sixth Army) was a part of Heeresgruppe Süd (Army Group South), and captured Kiev, Belgorod, Kharkov and Kursk. In September 1941, Reichenau reportedly wrote to Adolf Hitler to suggest that Ukrainians and White Russians, who initially viewed the German army as liberators, should be recruited to fight against the Bolsheviks. Hitler rejected this idea, telling Reichenau to stop interfering in political matters. Later that month Reichenau wrote again to Hitler on this subject, warning him of the dangers of large-scale partisan warfare in the Soviet Union. His advice was ignored, but his persistence in challenging Hitler's opinion was noted. During its offensive into Russia, the German army was confronted with a number of superior tank designs. Reichenau inspected the Soviet tanks he came across, entering each tank and measuring its armour plate. According to general staff officer Paul Jordan, after examining a T-34, Reichenau told his officers "If the Russians ever produce it on an assembly line we will have lost the war." On 15 January 1942 he suffered a hemorrhagic stroke after a trail run in harsh cold weather, and it was decided to fly him from Poltava to a hospital in Leipzig, Germany. He is often said to have been killed in a plane crash in Russia, although Görlitz writes that the plane merely made an emergency landing in a field and that Reichenau actually died of a heart attack. His death coincided with a propaganda offensive conducted by the Polish underground, Operation Reichenau, the goal of which was to discredit Reichenau, in the eyes of the German leadership, as a man who had allegedly been plotting to overthrow the Nazi régime, thus sowing distrust between the Nazi political leadership and its military command and punishing one of the German generals responsible for war crimes in Poland. The coincidence of such propaganda with Reichenau's death became a fertile ground for conspiracy theories, which allege that Reichenau might actually have been killed by the Nazi secret services.

Reichenau supported the work of the SS Einsatzgruppen in exterminating the Jews in the occupied Soviet territories. On 19 December 1941, Hitler sacked Walther von Brauchitsch as Commander-in-Chief and tried to appoint Reichenau to the post. But again the senior Army leaders rejected Reichenau as being "too political", and Hitler appointed himself instead. 

Source :
https://commons.wikimedia.org/wiki/File:Bundesarchiv_Bild_169-0946,_Russland,_General_Friedrich_Paulus_mit_Offizieren.jpg