Nurphoto | Nurphoto | Getty Images OpenAI Head of Sales James Dyett announced on Monday that he is leaving his role, the latest in a string of high-profile departures at the artificial intelligence company. Dyett joined OpenAI in 2023, right as the company underwent a period of explosive growth following the launch of its ChatGPT chatbot. OpenAI is now valued at more than $850 billion by private investors, and Dyett led its enterprise sales and its application programming interface (API) sales at different points during his tenure. "The timing feels right," Dyett wrote in a post on X on Monday. "I'm drawn back to the early stages of company building, and OpenAI is in a strong place." Dyett's departure comes after a number of executive leadership shakeups at OpenAI in recent months. Fidji Simo , OpenAI's product and business chief, announced last month that she would take  medical leave  because of a worsening  neuroimmune condition .…