D. A. Evans The Aldol Reaction: Metal-Centered Chirality Chem 206 Masamune. Sato, Kim Wollmann J. Am. Chem. Soc. 1986. 108. 8279-828 disfavored SCEt3 (95%ee) favored DIPEA SETs SCEt30°c,1h ScEt RCHO Yield, antisyn ee%(corrected) n-PrCHO 91 i-PrCHO 85 t-BuCHO 32:1 33:1 Chem 3D RCHO SCEt3 RCHO Yield, ee %(corrected Analogous Carbonyl Allylation n-PrCHO Masamune, Sato, Kim, Wollmann J. Org. Chem. 1987, 52, 4831 t-BuCHO 8753 HcHO favored See analogous study by Reetz Reetz Tetrahedron lett. 1986. 4721 Rcho Me enantioselection: 95-97%O SCEt3 Me TfO–B Me Me O BR*2 Me SCEt3 O SCEt3 BR*2 n-PrCHO i-PrCHO t-BuCHO c-C6H11CHO PhCHO n-PrCHO i-PrCHO t-BuCHO c-C6H11CHO PhCHO RCHO RCHO O SCEt3 Me BR*2 HO R SCEt3 O O R SCEt3 HO Me Cl–B Ph Ph Me B Me Me B O H Me O H R S R Me Me O B O Me Me S Me H H R R HO Me R HO Me R SCEt3 O O R SCEt3 Me HO R Me HO Reetz Tetrahedron Lett. 1986, 4721 See analogous study by Reetz disfavored D. A. Evans The Aldol Reaction: Metal-Centered Chirality Chem 206 Yield, % 82 81 71 95 78 ee % (corrected) 87 (91) 87 (92) 94 (98) 86 (90) 88 (92) + RCHO -78 °C 3 ® 10 h ee % (corrected) 93 (98) 95 (99) 96 (99.9) 93 (98) 96 (99.8) anti/syn 33:1 30:1 30:1 32:1 33:1 Yield, % 91 85 95 82 (71) 3 ® 36 h -78 °C + RCHO (95 % ee) DIPEA Masamune, Sato, Kim, Wollmann J. Am. Chem. Soc. 1986, 108, 8279-8281. 0 °C, 1 h favored Masamune, Sato, Kim, Wollmann J. Org. Chem. 1987, 52, 4831 Analogous Carbonyl Allylation favored + RCHO syn:anti, 96:4 enantioselection: 95-97% Chem 3D