Question

6. Predict which of the following two isomers (cis- or trans-) will undergo an E2 elimination under the treatment with EtoNa in EtOH more rapidly. A) For the explanation of the reaction rate, draw chair conformations for each isomer, determine which conformation is more stable . B) Draw the major product and the mechanism of the reactions. CI cis-isomer trans-isomer

Answer 1

ch- isomer H isoner HD from-isomer tram somer stabully Now, in between cis and from isomer from somer is more stash tham is-somer and as m in cause of cis-tron som there is two syn diaxial interaction Caxial c-H with axial (-u). no such interaction takes place in con of troms somer. Honue from somer is more stabl. Ez elimination reaction: 77 CAEL Na +1011 H. H o chino min. Inch-comer H & cu are anti with respect to each other. which is the man geometrical requirement for E2 pleomatus and we get 4-tertiary butyl cyclohexene ano tmal product. - a DEZ ta r a NUDEH PELOH X Here H and ce are not antito each other. So E2 elemnation reaction inot possible. . Here also flipping to not possible due to presence of the group otherwise it creat syn-1,3-deaxial intor acton le every unstable)

this both aubstituent occupy equatun Positing Hence Taan-isomen chain Cmfomatin Case mare 8table CI H Mone stable Cis-igomen will indengo Ellimination reaction(E2) because in thie Cce Pnoton is atpesiplanas de leasig groupt) In trans iaomen thene is ae Pouton anti peaiplanan mat undengo E 2 to ce' Tnans 12omen will reaction B aue Abstruction ot Proton by bue and Temoval of Leavioy 3noup tuks Plac IMaror Pnoduct)

Answer 2

ch- isomer H isoner HD from-isomer tram somer stabully Now, in between cis and from isomer from somer is more stash tham is-somer and as m in cause of cis-tron som there is two syn diaxial interaction Caxial c-H with axial (-u). no such interaction takes place in con of troms somer. Honue from somer is more stabl. Ez elimination reaction: 77 CAEL Na +1011 H. H o chino min. Inch-comer H & cu are anti with respect to each other. which is the man geometrical requirement for E2 pleomatus and we get 4-tertiary butyl cyclohexene ano tmal product. - a DEZ ta r a NUDEH PELOH X Here H and ce are not antito each other. So E2 elemnation reaction inot possible. . Here also flipping to not possible due to presence of the group otherwise it creat syn-1,3-deaxial intor acton le every unstable)