457625-39-7Relevant academic research and scientific papers
A new synthetic route to enantiomerically pure axially chiral 2,2′-bipyridine N,N′-dioxides. Highly efficient catalysts for asymmetric allylation of aldehydes with allyl(trichloro)silanes
Shimada, Toyoshi,Kina, Asato,Hayashi, Tamio
, p. 6329 - 6337 (2003)
New axially chiral 2,2′-bipyridine N,N′-dioxides 1 were obtained in an enantiomerically pure form by way of cyclic diesters 6 or 7 which were formed by the esterification of diols 2 with (R)-2,2′-bis(chlorocarbonyl)-1,1′-binaphthalene (5). Epimerization of the kinetic products at the ester formation (Rnap,Spyr)-6 to the thermodynamically stable isomers (Rnap,Rpyr)-7 was observed in refluxing toluene or in the presence of trifluoroacetic acid. One of the N,N′-dioxides 1a which is substituted with phenyl groups at the 6 and 6′ positions was found to be highly catalytically active and enantioselective for the asymmetric allylation of aldehydes with allyl(trichloro)silane giving homoallyl alcohols.
A novel axially chiral 2,2′-bipyridine N,N′-dioxide. Its preparation and use for asymmetric allylation of aldehydes with allyl(trichloro)silane as a highly efficient catalyst
Shimada, Toyoshi,Kina, Asato,Ikeda, Syushiro,Hayashi, Tamio
, p. 2799 - 2801 (2007/10/03)
(Matrix presented) New axially chiral 2,2′-bipyridine N,N′-dioxides were obtained by a new method that does not involve any procedures for the separation of enantiomers. One of the dioxides, (R)-3,3′-bis(hydroxymethyl)-6,6′-diphenyl-2,2′-bipyridine N,N′-dioxide, exhibited extremely high catalytic activity for the asymmetric allylation of aldehydes with allyl(trichloro)silane. The allylation of aromatic aldehydes proceeded in the presence of 0.01 or 0.1 mol % of the dioxide catalyst to give the corresponding homoallyl alcohols of up to 98% ee.
