No, helicopters do not have ejector seats because they would eject the pilot into the helicopter's rotor system.  During an emergency or other loss of power, helicopter pilots auto-rotate.  Auto-rotation is the decoupling of the rotor system from the engines to allow upward air flow to drive the rotor system at a faster than normal rate, providing kinetic energy that can be traded to arrest the helicopter's rate of descent.  To initiate auto-rotation, the helicopter pilot flattens the pitch in the rotor system's blades, reducing drag, and allowing the upward flow of air to drive its rotation.  When the helicopter is 100-150 feet above the ground, the pilot will then aggressively increase the pitch of the rotor system's blades, temporarily increasing lift and cushioning the helicopter's landing.