Marschall, Helga; Penninger, Josef; Weyerstahl, Peter, Liebigs Annalen der Chemie, 1982, # 1, p. 49 - 67
作者:Marschall, Helga、Penninger, Josef、Weyerstahl, Peter
DOI:——
日期:——
MARSCHALL, H.;PENNINGER, J.;WEYERSTAHL, P., LIEBIGS ANN. CHEM., 1982, N 1, 49-67
作者:MARSCHALL, H.、PENNINGER, J.、WEYERSTAHL, P.
DOI:——
日期:——
US3939207A
申请人:——
公开号:US3939207A
公开(公告)日:1976-02-17
Fluorinated Organocatalysts for the Enantioselective Epoxidation of Enals: Molecular Preorganisation by the Fluorine-Iminium Ion Gauche Effect
作者:Eva-Maria Tanzer、Lucie E. Zimmer、W. Bernd Schweizer、Ryan Gilmour
DOI:10.1002/chem.201201316
日期:2012.9.3
The fluorine‐iminium ion gauche effect is triggered upon union of a secondary β‐fluoroamine and an α,β‐unsaturated aldehyde, providing a useful strategy for controlling the molecular topology of intermediates that are central to organocatalytic processes. The β‐fluoroamine (S)‐2‐(fluorodiphenylmethyl)pyrrolidine (1) is an effective catalyst for the enantioselectiveepoxidation of α,β‐unsaturated aldehydes
respectively, undergo 1,3-dipolarcycloaddition with ethylvinylether, leading to the tetrahydrofuran system. The cycloaddition proceeds with high regioselectivity affording predominantly the exo-adduct. However, the ylide from the mononitrile 1 and dinitrile 4 gives little or no adduct. The observed regioselectivity and the difference of the reactivity in these cycloadditions can be nicely accommodated