Why was Adolph Hitler so vehemently opposed to an alliance with Stalin?

Hitler could certainly have drawn out WWII had he not opened the war on the Eastern Front with Russia. Stalin actually wanted to cooperate with Germany against the West. But Hitler’s hatred of communism wouldn’t let him even form an alliance of convenience with Stalin, which he could certainly have reversed if he were able to defeat the Western Allies. Why was Hitler so against any alliance with Stalin. Was his belief in fascism, and its embrace of corporatocracy the main issue, or did it have more to do with Stalin himself?