You can't "work," but you can engage in a limited number of "business" activities.
Permissible activities include:
- facilitating business transactions for a foreign company (for instance, taking orders for goods or services to be produced outside of the US);
- negotiating contracts;
- attending business meetings;
- attending conferences or seminars;
- conducting independent research;
- pitching to investors;
- evaluating investment opportunities, including investments made in anticipation of applying for an E2 visa;
- forming a company; and
- opening a company bank account.
Activities that go beyond the scope of those described above, such as performing productive, day-to-day work for the company or actively managing employees, vendors, contractors, etc., are not permitted on a standard B1 visa.