Substitution & Elimination 7: Regio- and Stereo-control in E2 Eliminations

The selectivity of the E2 reaction is described -- the preference for more highly-substituted alkene, except in the case of the use of very bulky bases; the requirement of the H and leaving group to be anti and periplanar; and the stereospecificity of some E2 reactions in which only one proton is positioned appropriately relative to the leaving group. (Expert Note: Although this video describes t-BuOK as the bulky base of choice for "Hoffman" elimination, we have recently transitioned to LDA as the reagent for this, simply because t-BuOK is the reagent we typically describe as the "proper" one to choose if you wish to select for E2 over SN2, even if you want the Zaitsev product. We do not usually use the "Zaitsev/Hoffman" nomenclature.)