b) cis-1,2-dibromo-1-hexene 6) 1,2-dichloro-1,2-dimethylcyclobutane has four the pairs of isomers as either enantiomers, diastereomers, or i possible stereoisomers shown below. Label dentical compounds. (10 pts) CI C Cl Cl Cl Cl 7) (a) Write a detailed mechanism for the E2 reaction of 2-bromobutane, showing the formation f both products. Use curved arrows to show the flow of electrons, and include any relevant formal charges, lone pairs of electrons, and stereochemistry. (4 pts) NaOEt HOEt, 50 °C Br