Organic Synthesis

An E1 elimination begins with the departure of a leaving group (hydroxyl in this case) and formation of a carbocation intermediate (step 1). This is the rate determining step. Abstraction of a proton from an adjacent carbon (step 2) sends two electrons down to fill the empty p orbital of the carbocation, forming a new p bond. The base in this step may be the leaving group, or another basic species in solution.