Evans, Duffy, Ripin Conformational Barriers to Rotation Olefin A-1, 2 Interactions-2 Chem 206 2-methyl-1-butene 2-methyl-2-propen-1-0/ 2 ,4 ΦqDeg) The Torsional Energy Profile The Torsional Energy Profile ①=180 d: 60 =120 ①=110 +2.68 +2.01 Φ=0 +1. 39 kcal +1.16 kcal 0.21 kcal +0.06 kcal Φ=1800 1 2 3 4 5 -180 -90 0 90 180 0 1 2 3 4 5 -180 -90 0 90 180 Evans, Duffy, & Ripin Conformational Barriers to Rotation: Olefin A-1,2 Interactions-2 Chem 206 (Deg) 2-methyl-1-butene E (kcal/mol) +2.68 kcal +1.39 kcal +0.06 kcal F = 180 F = 110 F = 50 F = 0 F = 0 F = 180 The Torsional Energy Profile (Deg) 2-methyl-2-propen-1-ol E (kcal/mol) The Torsional Energy Profile F = 0 F = 180 F = 0 F = 60 F = 120 F = 180 +0.21 kcal +1.16 kcal +2.01 kcal H C H C Me H H H C H C Me H H H C H Me H H C C Me H H C Me H H Me Me H H C C Me H H Me Me H C H C Me H H OH OH HO H C H H C Me H OH HO H H C C Me H H H H C C Me H H H H C C Me H H F F