111843-46-0Relevant articles and documents
Catalytic asymmetric epoxidation of α,β-unsaturated carboxylic acid imidazolides and amides by lanthanide-BINOL complexes
Ohshima, Takashi,Nemoto, Tetsuhiro,Tosaki, Shin-Ya,Kakei, Hiroyuki,Gnanadesikan, Vijay,Shibasaki, Masakatsu
, p. 10485 - 10497 (2007/10/03)
Highly enantioselective catalytic asymmetric epoxidation of α,β-unsaturated carboxylic acid imidazolides and simple amides was developed. In the presence of 5-10mol% of lanthanide-BINOL complexes, the reaction proceeded smoothly with high substrate generality. In particular, in the cases of α,β-unsaturated amides, there was nearly perfect enantioselectivity (>99% ee). The corresponding epoxides were successfully transformed into many types of useful chiral compounds such as α,β-epoxy esters, α,β-epoxy amides, α,β-epoxy aldehydes, α,β-epoxy β-keto ester, and α- and β-hydroxy carbonyl compounds. B3LYP density functional studies were performed to predict substrate reactivity.
Efficient synthesis of chiral α,β-epoxyesters via a cyclic sulfate intermediate
He, Linli,Byun, Hoe-Sup,Bittman, Robert
, p. 2071 - 2074 (2007/10/03)
An efficient synthesis of chiral α,β-epoxyester 1 from chiral 2,3- dihydroxyester 2 has been developed. Ester 2 is converted to the corresponding cyclic surfate 3, which is opened with either LiBr in THF or Bu4NBr in acetone at rt to furnish 2-bromo-3-hydroxyester 4. Treatment of 4 with K2CO3 in methanol at low temperature gives α,β-epoxyester 1 in excellent overall yield and in the same ee as in the starting diol.
