Direct Asymmetric α‐Fluorination of Aldehydes

Abstract

Linear and branched aldehydes are asymmetrically α‐fluorinated with L‐proline‐ and pyrrolidine‐based organocatalysts (see scheme; NFSi: N‐fluorobenzenesulfonamide). In the first case, yields and enantioselectivities were high; in the second, the yields remained high and the enantioselectivities were moderate. Significantly, linear aldehydes were only monofluorinated.

Molecular diversity of four–component synthesis of pyrazole based pyrido[2,3-d]pyrimidine-diones in water: a green synthesis

“…45,46 Thus when we should create a stereogentic center in our final product, we frequently used it. (Scheme 3) In an attempt towards the asymmetric synthesis of our target molecule, initially The model reaction was conducted at 25 °C using L-proline as the catalyst.…”

Direct organocatalytic Wittig/Hetero-Diels-Alder reactions in one-pot: synthesis of highly-substituted tetrahydropyranones

“…[11][12][13] Also, Jørgensen and Juhl developed the enantioselective inverse-electron-demand HDA reaction with an enamine generated in situ from an aldehyde and chiral amine with enones under organocatalysis. [14][15][16][17][18] As part of our program to engineer novel asymmetric assembly reactions that proceed in environmentally-sound conditions under amine-catalysis, 8,[19][20][21][22][23][24][25][26][27] we sought to extend the use of chiral organo-amines as catalysts for asymmetric HDA reactions.…”

Enantioselektive α‐Fluorierung von Carbonylverbindungen: Organo‐ oder Metallkatalyse?

“…In diesen Veröf-fentlichungen berichteten die Gruppen um Jørgensen, [13] Barbas [14] und MacMillan [15] jeweils über hoch enantioselektive Varianten organokatalytischer a-Fluorierungen von Aldehyden mit sekundären Aminen oder Aminsalzen als Katalysatoren. Die Reaktionen sind in Schema 5 zusammengefasst.…”

“…[12] Schema 5. Hoch enantioselektive organokatalytische a-Fluorierungen von Aldehyden nach Jør-gensen, [13] Barbas [14] und MacMillan.…”

“…In Anbetracht der Schwierigkeiten bei der enantioselektiven a-Fluorierung von Ketonen [12] [13,14] Schema 7. Beispiele hoch enantioselektiver a-Fluorierungen von Carbonylverbindungen mit dem Katalysator Ni II -dbfox nach Shibata et al [19] Schema 8.…”