Good morning mister/doctor/professor Smith. Good afternoon mister/doctor/professor Smith.

Use the boss' proper name, eg: "Good morning/afternoon Mr Wentworth". This is respectful to him, and yourself. Calling him "boss" or "sir" lowers your own status, and makes you sound like a slave. ;)

Olá, pode falar "Good morning boss" pra bom dia chefe e "Good afternoon boss" pra boa tarde chefe.