Organic dye photocatalyzed α-oxyamination through irradiation with visible light
作者:Hongjun Liu、Wei Feng、Choon Wee Kee、Yujun Zhao、Dasheng Leow、Yuanhang Pan、Choon-Hong Tan
DOI:10.1039/b924609f
日期:——
Rose Bengal, an organic dye, was used as a visible light photocatalyst to investigate novel α-oxyamination reactions between 1,3-dicarbonyl compounds and a free radical (TEMPO). Compounds that are difficult to obtain such as quaternary fluorinated compounds were synthesized using this method. This visible light photocatalytic reaction can also be performed in water.
Asymmetric Mannich Reaction of Fluorinated Ketoesters with a Tryptophan-Derived Bifunctional Thiourea Catalyst
作者:Xiao Han、Jacek Kwiatkowski、Feng Xue、Kuo-Wei Huang、Yixin Lu
DOI:10.1002/anie.200903635
日期:2009.9.28
Fluorinated quaternary stereocenters: A novel bifunctionalcatalyst 1 derived from natural tryptophan promoted the Mannichreaction of α‐fluoro‐β‐ketoesters to afford fluorinated chiral molecules containing vicinal quaternary and tertiary stereogenic centers with exceptional enantioselectivity. An unprecedented α‐fluoro‐β‐lactam was also prepared by this method (see scheme; Boc=tert‐butoxycarbonyl)
available Cinchonaalkaloid as catalyst, the asymmetric allylic alkylation of Morita-Baylis-Hillmancarbonates, with alpha-fluoro-beta-keto esters as nucleophiles, have been successfully developed. A series of important fluorinated adducts, with chiral quaternary carbon centres containing a fluorine atom, was achieved in good yields (up to 93%), with good to excellent enantioselectivities (up to 96%
Activation of the hypervalent fluoroiodane reagent by hydrogen bonding to hexafluoroisopropanol
作者:Harsimran K. Minhas、William Riley、Alison M. Stuart、Martyna Urbonaite
DOI:10.1039/c8ob02236d
日期:——
Hexafluoroisopropan-2-ol (HFIP) is an excellent solvent for promoting fluorinations with the hypervalent fluoroiodane reagent 1 and crucially, it removes the need for transition metals or TREAT-HF activators. The fluoroiodane reagent 1 was used in HFIP to monofluorinate 1,3-ketoesters and to fluorocyclise unsaturated carboxylicacids in excellent yields under mild reaction conditions.