D. A. Evans Introduction to Complex Aldol Bond Constructions Chem 206 he Altohyrtin Synthesis: An example of polypropionate assembage Model studies OB(C-Hexh2 3°C Diastereoselection 97. 3 Background H Evans, Trotter, Coleman, Cote, Dias, Rajapakse, Tetrahedron 1999, 55, 8671-8726 Meo R=PMB69:31 iPr Aldol o OTBS M The Aldol Fragment Coupling Me oTBs B(cHexh2 Tro OTBS each fragment were ev 人 Model studies Meo a OTBS Diastereoselection 90: 10(70%) OTBS 2. 1 mixture of diastereomersO O MeO O H O O HO H O Me AcO H OH O O OH Me Me H OAc Me OH H OH O H OH Me HO H X H H H H H H H H O Me TBSO O O Me Et Me OB(c-Hex)2 O O TESO H OTBS Me TESO Me H O H O O MeO H OTBS H TrO H Me O M O O TESO H OTBS TESO Me O O MeO H OTBS H TrO H O Me OH Me H O O MeO H OTBS H TrO H Me O B(c-Hex)2 Me Me H O O O MeO H OTBS H TrO H O Me Me Me OH Me H O OR iPr iPr OB(Chx)2 Me iPr BR2 O O O MeO H OTBS H TrO H O Me B(cHex)2 O O TESO H OTBS TESO Me O O MeO H OTBS H TrO H O Me OH Me H iPr OH iPr O OR Me O Me OR Me OH iPr iPr OH Me TBSO O O Et Me Me O O O TESO H OTBS Me TESO Me H O H D. A. Evans Introduction to Complex Aldol Bond Constructions Chem 206 The Altohyrtin Synthesis: An example of polypropionate assembage Evans, Trotter, Coleman, Côté, Dias, Rajapakse, Tetrahedron 1999, 55, 8671-8726. Aldol ? Reaction The stereochemical determinants from each fragment were evaluated pentane, -78 °C 2:1 mixture of diastereomers Diastereoselection 97:3 -78 °C 14 Model Studies major : S others R = TBS R = PMB 99 : 1 93 : 7 R = PMB 69:31 Background Model Studies Diastereoselection 90:10 (70%) The Aldol Fragment Coupling