D. A. Evans Enolate Alkylation: Chiral Amide Enolates Chem 206 hiral amide enolates Amide Hydrolysis HOH,c O M-NR2 R-X Evans. Takacs intramoleclar general base catalysis Tet.Lett1980,21,42334236 Br964(98%) Me Br98:2(84%) Applications in lonomycin synthesis Chem 3D model lonomycin Calcium Complex Meho Mel JAcS1990,112,52905313 OH Me?HC 84% The nature of enolate chelation is ambiguous. Nitrogen chelation is a real possibility Me?Hc PhCH=CHCH2 Br diastereoselection 99: 1 o CH2OH OH Me 83% Myers, JACS 1997, 119, 6496 diastereoselection 97: 3Ph Me I Ph N O Me Me CH2OH Me R O H2N O Me2HC O O N O Me Li Me N O O O Me2HC + 14 12 14 HOH2C O Me N M-NR2 O M Me N Li O R–X R–X Br Br Me Me Li N Me OH Me Me O R–X R HOH2C O Me N R N Me HOH2C O Li Li Me R OH O O CH2OH N R Me H + PhCH=CHCH2Br N O C O H H H R O H O N R HO H2O H Me H Me OH Me O O Me Me Me O Me OH OH Me O Me O O Me Ca Ph Me N O O O Me2HC O HN O R Me Me N Li O O K 14 14 JACS 1990, 112, 5290-5313 Applications in Ionomycin synthesis HCO3 - H2O, 5 min Amide Hydrolysis intramoleclar general base catalysis 1 9 17 Ionomycin Calcium Complex 14 12 83% 84% 14 LDA diastereoselection 97:3 diastereoselection 99:1 Chiral Amide Enolates Evans, Takacs, Tet. Lett. 1980, 21, 4233-4236 Chem 3D model 98:2 (84%) (minor) (major) 96:4 (98%) D. A. Evans Enolate Alkylation: Chiral Amide Enolates Chem 206 The nature of enolate chelation is ambiguous. Nitrogen chelation is a real possibility. Myers, JACS 1997, 119, 6496