Hitler's war was base don trying to get the British to join him and have an Aryan master empire or forcing the British to surrender. Hitler had full access to ALL Soviet raw materials, including oil. The Soviets supplied 80% of all materials the Nazis used in WWII.
The Battle of Britain was in Hitlers view the end game. If he won the war was over as Europe, Asia, Africa, and the Arab world would have been on his side. After the decisive victory of the British air force Hitlers heart was broken. He knew the war was lost, simply put he could not win.
His attack on his greatest allie, Stalin, was more to do with his scorching earth policy than any military gain. He wanted to kill as many German and allied troops as possible before the inevitable defeat and his own death.
The BOB led to the unwinable and irrelevant invasion of the Soviet Union. Even if Hitler had won his army would have been weaker and in a worse position than before.
As I said ALL raw materials from the Soviet Union were available to the Germans without the need to invade.
Hitler's main war aim was to create "lebensraum" or living space for the expansion of Germany. The need for "lebensraum" was described by him in his book "Mein Kampf" (My Struggle)published in the 1920's. Hitler believed that the place for this expansion was to the East of Germany. For this reason he invaded Poland in 1939 but first had to deal with France and England, who came to Poland's aid, to the West in 1940 before attacking Russia to the East in 1941.
Germany had a Non-Aggression Pact with the Soviet Union. This gave Stalin a strange sense of peace and respect for Hitler. Hitler, however, was not so peaceful. He, and his military advisor's knew that the oil in the Soviet Union would be very necessary if Germany was to continue fighting for a long time. Hitler decided to try to take care of the Soviets before the US entered the war.