M.C. White, M.S. Taylor Chem 15 Nu attack on olefins -332 Week of november 25, 2002 Application of an intramolecular Wacker oxidation in the synthesis of garsubellin A Napdcly(40 mol%) t-BuOoH ACOH/H20 ACOH/H2O -HcI reductive Garsubellin a elimination HCIPdll t-BuOOH Pd"CI 阝- hydride Pdc CP心 d la Shibasaki OL 2002(4)859
M.C. White, M.S. Taylor Chem 15 Nu attack on Olefins -332- Week of November 25, 2002 Application of an intramolecular Wacker oxidation in the synthesis of Garsubellin A O O O O HO Garsubellin A Shibasaki OL 2002 (4) 859. O O O O O Na2PdCl4 (40 mol%) t-BuOOH O O O OH HO O O O OH HO Cl2PdII O O O O HO PdIICl2 t-BuOOH PdIICl2 O O O O HO O O O O HO PdIICl AcOH / H2O 69% AcOH / H2O Pd0 – HCl – HCl O O O O HO HClPdII H HCl β-hydride elimination reductive elimination of HCl
M.C. White, Chem 153 Nu attack on olefins -333 Week of November 25. 2002 Tandem oxopalladation/Heck-type cyclization F3COCo OCOCF3 20 mol% OBz 0(4 eq)CH,Ch,0C Sasai JACS 2001(123)2907 27%60%ee +"ocoCF3 HO→ OBz 6-endo-tr OCF3 OCOCF3 2HOCOCF3+ OCOCE HOCOCF3
M.C. White, Chem 153 Nu attack on Olefins -333- Week of November 25, 2002 HO OBz PdII OCOCF3 N N OCOCF3 O OBz PdII N N H OCOCF3 O OBz PdII N N HOCOCF3 H O OBz PdII N N H OCOCF3 O OBz PdII N N HOCOCF3 O OBz PdII N N H O OBz OCOCF3 PdII N N H OCOCF3 O H OBz Pd N N H OCOCF3 O H OBz Pd0 N N O O OH OH PdII N N OCOCF3 OCOCF3 * 6-endo-trig 2 HOCOCF3 + Proposed mechanism: Tandem oxopalladation/Heck-type cyclization Sasai JACS 2001 (123) 2907. HO OBz O N N O H H i-Pr i-Pr i-Pr i-Pr PdII F3COCO OCOCF3 O O CH2Cl2, 0oC O H OBz O OBz O OBz 20 mol% (4 eq) 68%, 95% ee (single diastereomer) + 5%, 45% ee 27%, 60% ee