The Nazis tried to woo union votes by showing support for the union causes, particularly the Transit workers who were on strike. The unions, however, were firmly in the corner of the communists and voted accordingly.
When Hitler came to power, his ‘Enabling Act’ allowed him to stifle strikes and bend the unions to his will.
Once elections were abolished, he didn’t need any groups ‘support’, only ‘submission.
The relationship between communism and unions has always been strong. As Lenin said, ‘Unions are the transmission belt between communism and the masses.’
Hitler was more pragmatic than other Nazis, for example, Ernst Rohm wanted to Nationalize all German industry and basically eliminate the German Business Class.
Hitler knew better, because he needed the Industrialists on his side, if he was to build up his war machine. That was one of the main reasons for “The Night of the Long Knives”, in order to placate the industrialists.
However, once the war was won, it’s very likely that the German Industrialists would face the same fate as the Jews, because they were not part of the Nazis’ long-term vision.