D. A. Evans Transition State Torsional Effects: Olefin Additions Chem 206 Martinelli. Torsional steering important in selectivity mCPBA 99: 1 diastereoselectivity mCPBA 50: 50 diastereoselectivity Authors propose that diastereoselection controlled by TS torsional effects Martinelli& Houk, J. Org. Chem. 1994, 59, 220463° 62° 74° 40° major Me O H Me O O H D. A. Evans Transition State Torsional Effects: Olefin Additions Chem 206 Martinelli: Torsional steering important in selectivity 99 : 1 diastereoselectivity 50 : 50 diastereoselectivity 99 : 1 diastereoselectivity Martinelli & Houk, J. Org. Chem. 1994, 59, 2204. mCPBA mCPBA mCPBA 89° major Authors propose that diastereoselection controlled by TS torsional effects