CHEM 2131 | E2 Mechanism

E2

the E2 mechanism uses ____ instead of nucleophiles

bases

Alkenes are more stable when they are ______ ______

highly substituted

regioselectivity

an E2 reaction that can form more than 1 product (differs in placement of double bond), with a major and minor product

stereoselectivity

a type of chemical reaction that preferentially forms one stereoisomer over another when multiple options are possible (trans)

the Zaitsev product refers to the most ___ product (or the most substituted)

stable

the Hoffman product refers to the most ____ proton

accessible (less steric hindrance)

antiperiplanar

Anti-periplanar in E2 reactions means the -hydrogen and the leaving group are on opposite sides of the molecule ( dihedral angle) in the same plane; allows rxn to occur efficiently

on a cyclohexane ring, an E2 reaction only occurs from the chair conformation in which the leaving group is ____; the H and Cl must be ___ to each other (on opposite sides)

axial, trans

when a fat base is used, the major product is the ___ product

Hoffman

when a skinny base is used, the major product is the ______ product

Zaitsev

an E2 reaction is _____ overall

exothermic

when determining if two products are the same, assess if the alpha carbon is a _____ _____, if it is not, determine which of the two beta carbons are the ___

chiral center, same

if there are two beta protons attached to a beta carbon (with sigma bond), there will be free ____ and two _____ will be produced, ___ and ___

rotation, stereoisomers, cis, trans

a fast E2 reaction occurs when the leaving group and beta H are both ___

axial