7- 1 7 E2 elimination requires that the H and the leaving group be anti-coplanar; in a chair cyclohexane, this requires that the two groups be trans diaxial. However, when the bromine atom is in an axial position, there are no hydrogens in axial positions on adjacent carbons, so no elimination can occur. 7- 1 8 c� hydrogens lrans diaxial lo lhe Br CH3 H Br-- axial (X)'" => � � 'Br � T -1 H H Br axial (DBr H C:::::>=Br � T �atOrial H (a) KOH � H + H (b) Showing the chair form of the decalins makes the answer clear. The top isomer locks the
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