Beta-agostic interactions can promote one type of these reactions in catalytic hydrogenation reactions. Xanthate pyrolysis is practically irreversible thanks to the formation of stable carbonyl sulfide and thiol byproducts in a reaction of this type named for Chugaev. Amines can be removed through exhaustive methylation followed by treatment with silver oxide in a reaction of this type named for (*) Hofmann. For bimolecular reactions of this (15[1])type, an anti-periplanar arrangement of (-5[1])atoms is (15[2])required. (-5[1])The unimolecular form of this reaction has the same (-5[1])intermediates as SN1 reactions, so its products compete with substitution products. For 10 points, name (10[2])these reactions that can form pi bonds (10[1])through E2 or E1 mechanisms. ■END■