TY - JOUR
T1 - Catalytic asymmetric epoxidation of α,β-unsaturated esters with chiral yttrium-biaryldiol complexes
AU - Kakei, Hiroyuki
AU - Tsuji, Riichiro
AU - Ohshima, Takashi
AU - Morimoto, Hiroyuki
AU - Matsunaga, Shigeki
AU - Shibasaki, Masakatsu
PY - 2007/7/2
Y1 - 2007/7/2
N2 - The full details of the asymmetric epoxidation of α,β- unsaturated esters catalyzed by yttrium complexes with biaryldiol ligands are described. An yttrium-biphenyldiol catalyst, generated from Y(OiPr) 3-biphenyldiol ligand-triphenylarsine oxide (1:1:1), is suitable for the epoxidation of various α,β-unsaturated esters. With this catalyst, β-aryl α,β-unsaturated esters gave high enantioselectivities and good yields (≤99% ee). The reactivity of this catalyst is good, and the catalyst loading could be decreased to as little as 0.5-2 mol % (the turnover number was up to 116), while high enantiomeric excesses were maintained. For β-alkyl α,β-unsaturated esters, an yttrium-binol catalyst, generated from Y-(OiPr)3-binol ligand-triphenylphosphine oxide (1:1:2), gave the best enantioselectivities (≤97% ee). The utility of the epoxidation reaction was demonstrated in an efficient synthesis of (-)-ragaglitazar, a potential antidiabetes agent.
AB - The full details of the asymmetric epoxidation of α,β- unsaturated esters catalyzed by yttrium complexes with biaryldiol ligands are described. An yttrium-biphenyldiol catalyst, generated from Y(OiPr) 3-biphenyldiol ligand-triphenylarsine oxide (1:1:1), is suitable for the epoxidation of various α,β-unsaturated esters. With this catalyst, β-aryl α,β-unsaturated esters gave high enantioselectivities and good yields (≤99% ee). The reactivity of this catalyst is good, and the catalyst loading could be decreased to as little as 0.5-2 mol % (the turnover number was up to 116), while high enantiomeric excesses were maintained. For β-alkyl α,β-unsaturated esters, an yttrium-binol catalyst, generated from Y-(OiPr)3-binol ligand-triphenylphosphine oxide (1:1:2), gave the best enantioselectivities (≤97% ee). The utility of the epoxidation reaction was demonstrated in an efficient synthesis of (-)-ragaglitazar, a potential antidiabetes agent.
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U2 - 10.1002/asia.200600309
DO - 10.1002/asia.200600309
M3 - Article
C2 - 17441160
AN - SCOPUS:34248189099
VL - 2
SP - 257
EP - 264
JO - Chemistry - An Asian Journal
JF - Chemistry - An Asian Journal
SN - 1861-4728
IS - 2
ER -