3708-36-9Relevant articles and documents
Catalytic asymmetric protonation of chiral calcium enolates via 1,4-addition of malonates
Poisson, Thomas,Yamashita, Yasuhiro,Kobayashi, Shu
supporting information; experimental part, p. 7890 - 7892 (2010/08/05)
Catalytic asymmetric protonation of chiral calcium enolates was performed. Chiral calcium enolates, prepared in situ from imides and malonates via 1,4-addition in the presence of catalytic amounts of Ca(OEt)2, Ph-PyBox, and achiral phenol, were smoothly protonated to afford adducts bearing tertiary asymmetric carbons in high yields with high enantioselectivities. The adducts were readily converted to optically active 2-substituted 1,5-dicarboxylic acid derivatives.
REACTIVITY OF 1-CYCLOPROPENE-1-LACTONES DEPENDENT ON THE SUSBSTITUTION DEGREE
Hashem, Md. Abul,Weyerstahl, Peter
, p. 2003 - 2010 (2007/10/02)
Reaction of the α-chloro lactone 10 with KOtBu gives the butoxy lactones 21 and 22; the seven membered derivative 11 leads 23 as the only isolable product.Formation of the α-substitution product 21 as well as the enhanced instability of the intermediates 12 and 13 in comparison to their methyl substituted homologues 5 and 6 show the kinetical stabilization by a methyl group at C-2.Products derived from a cyclopropeno lactone of type A could not be detected.