Stork Delivers more siMe, TBAF-DMF °c75% then H2O2 80% TBAF-DMF TBAF-DMF CO Et CO,Et hen H2O2 CoEt Note ed compound is epimerized by fluoride ion in the course of desilylation other Interesting Examples from Sieburth KE.Ho 1: 1 mixture of diastereomers 46%2s06 33A-043/149611:31PMO SiMe2 CO2Et SiMe2 O CO2Et SiMe2 O CO2Et O SiMe2 CO2Et OH CO2Et OH OH CO2Et OH CO2Et OH CO2Et OH 80 °C 90% O O O SiPh2 O O H Si Ph Ph O SiPh2 O H H O OH OH H Stork Delivers More: TBAF-DMF then H2O2 80% TBAF-DMF then H2O2 TBAF-DMF 60 °C 75% O SiMe2 Note: Selectivity in each case results from endo-addition with respect to the ester, even when the product contains four contigous cis stereocenters. This highly strained compound is epimerized by fluoride ion in the course of desilylation. 190 °C retro-Diels-Alder Bu TBAF-DMF 60 °C ‡ SiMe2 O hetero-Diels-Alder 1 isomer Bu KF, H2O2 75%, 2 steps Other Interesting Examples from Sieburth: SiMe2 O 190 °C 1:1 mixture of diastereomers Bu DDQ 46%, 2 steps 33A-04 3/14/96 11:31 PM