If your work is outside the city and you cannot hear the voice of the muezzin without amplification, then Jumu’ah prayer is not obligatory on you, and you can pray Zuhr. 

But if you are inside the city, or you are outside but you can hear the adhaan, then it is obligatory for you to attend Jumu’ah prayer. Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) was asked about some workers who are not permitted by their employers to attend Jumu’ah on the grounds that they work as guards on a farm.  

He answered: 

If these workers are so far from the mosque that they would not be able to hear the adhaan without a loudspeaker, and they are outside the town, then they do not have to pray Jumu’ah. The workers may rest assured that there is no sin on them if they stay on the farm and pray Zuhr. But we advise their employer to give them permission (to attend Jumu’ah) because that is better for him and better for them. 

Liqa’ al-Baab al-Maftooh, 1/413 

The Standing Committee was asked about a young man who works as a servant, and his employer does not allow him to pray in the mosque. He beats him if he prays in the mosque and threatens to send him back to his country. 

They replied: 

The five daily prayers should be offered in the mosque in congregation, so you have to perform them in congregation in the mosque. You have to be patient and seek reward in doing that, and Allaah will grant you ease after hardship. Allaah says (interpretation of the meaning): 

“And whosoever fears Allaah and keeps his duty to Him, He will make a way for him to get out (from every difficulty).

And He will provide him from (sources) he never could imagine. And whosoever puts his trust in Allaah, then He will suffice him. Verily, Allaah will accomplish his purpose. Indeed Allaah has set a measure for all things”
[al-Talaaq 65:2-3] 

And you should note that there is no obedience to any created being if it involves disobedience towards the Creator, so be with Allaah and Allaah will be with you. 

Fataawa al-Lajnah al-Daa’imah. 

Based on this, our advice to you is to try to reach an agreement with your boss and explain the situation to him, and offer to make up the time spent attending Jumu’ah so that you will take care of your work properly. If he accepts that, all well and good, otherwise there is nothing good about work that prevents you from praying. Whoever gives up a thing for the sake of Allaah, Allaah will compensate him with something better. 

And Allaah knows best.