De Novo Synthesis of 2-Substituted syn-1,3-Diols via an Iterative Asymmetric Hydration Strategy
摘要:
The enantioselective syntheses of several protected 4-substituted syn-3,5-dihydroxy carboxylic esters have been achieved from the corresponding achiral (E,E)- or (E,Z)-1,3-dienoates. The route relies upon an enantio- and regioselective Sharpless dihydroxylation and a palladium-catalyzed reduction to form gamma-substituted delta-hydroxy-1-enoates. The resulting delta-hydroxy-1-enoates are subsequently converted into benzylidene-protected 4-substituted syn-3,5-dihydroxy carboxylic esters in one step. The benzylidene-protected 3,5-dihydroxy carboxylic esters are produced in good overall yields (20-54%) and high enantiomeric excess (73- 97% ee).
Formal Total Synthesis of RK-397 via an Asymmetric Hydration and Iterative Allylation Strategy
作者:Haibing Guo、Matthew S. Mortensen、George A. O’Doherty
DOI:10.1021/ol801055b
日期:2008.7.17
A formal totalsynthesis of the oxopentaene macrolide antibiotic RK-397 has been achieved. Nine stereocenters were established by a combination of allylation and our asymmetric hydration reactions and a 1,5 anti-selective aldol reaction. The synthesis proceeded in 19 steps from simple achiral conjugated dienoates.