2,4-Dioxoesters 1a–c are selectively converted into optically active 2-hydroxy-4-oxoesters 2a–c by hydrogenation with chiral rhodium-aminophosphane-phosphinite catalysts (82–88% ee) or ruthenium-bisphosphane catalysts (52–67% ee). Direct one-pot hydrogenation of 2,4-dioxoesters 1a–c to 2-hydroxy-4-butyrolactones 4a–c proceeds in high yields; catalytic activities, chemo-, dia-, and enantioselectivities
Stereoselective synthesis of cis- or trans-2,4-disubstituted butyrolactones from Wynberg lactone
作者:Ashok Ganta、Julia L. Shamshina、Lauren R. Cafiero、Timothy S. Snowden
DOI:10.1016/j.tet.2012.04.107
日期:2012.7
(R)-Wynberg lactone was used to prepare various asymmetric 2,4-disubstituted butyrolactones in three to four steps. Attainment of any possible stereoisomer, based upon commencement from (R)- or (S)-4-trichloromethyl-2-oxetanone, and the capacity to install disparate substituents at C2 make this approach particularly versatile.