Is it permissible for an employee to inform a distribution company to obtain a commission from it if it (the distribution company) reaches an agreement with his employer without his intervention?

There is no impediment to acting as an intermediary between two companies for a commission, provided that this is not part of your job or that it is outside your official working hours, unless permitted by the company. You must be keen on safeguarding your company's interests, so the commission should not affect your ability to provide full advice to it.