Metal-Free Catalytic Asymmetric Fluorination of Keto Esters Using a Combination of Hydrogen Fluoride (HF) and Oxidant: Experiment and Computation
作者:Roman Pluta、Patricia E. Krach、Luigi Cavallo、Laura Falivene、Magnus Rueping
DOI:10.1021/acscatal.7b03118
日期:2018.3.2
for the catalytic asymmetric fluorination has been developed. The catalyst was used in the asymmetric fluorination of carbonyl compounds, providing the products with a quaternary stereocenter with high enantioselectivities. Chiral hypervalent iodine difluoride intermediates were generated in situ by treatment of the catalyst with an oxidant and hydrogen fluoride as fluoride source. As such, the α-fluorination
Enantioselective Fluorination Mediated by Cinchona Alkaloid Derivatives/Selectfluor Combinations: Reaction Scope and Structural Information for <i>N</i>-Fluorocinchona Alkaloids
Cinchona-alkaloid/Selectfluor combinations efficiently fluorinate a variety of carbonyl compounds in a highly enantioselective manner to furnish chiral alpha-fluorocarbonyl compounds. The DHQB/Selectfluor combination is effective for the enantioselective fluorination of indanones and tetralones 1 in up to 91% ee. The first enantioselective syntheses of chiral derivatizing reagents 3 was accomplished with high ee and in
several limitations in both chemical yields and enantioselectivities of the fluorinated products. We present here the background of our personal story of the enantioselectivefluorination reaction and some successful applications of the methods to the design and synthesis of biologically active products. Two novel approaches using cinchonaalkaloid/Selectfluor® combinations and chiral ligands/metal complexes
Iron(iii)–salan complexes catalysed highly enantioselective fluorination and hydroxylation of β-keto esters and N-Boc oxindoles
作者:Xin Gu、Yan Zhang、Zhen-Jiang Xu、Chi-Ming Che
DOI:10.1039/c4cc01631a
日期:——
Chiral iron(III)âsalan complexes catalysed highly enantioselective α-fluorination and α-hydroxylation of β-keto esters and N-Boc oxindoles to give the corresponding products in high yields and good-to-excellent ee values under mild reaction conditions.
Trifluorinated Tetralins via I(I)/I(III)‐Catalysed Ring Expansion: Programming Conformation by [CH
<sub>2</sub>
CH
<sub>2</sub>
] → [CF
<sub>2</sub>
CHF] Isosterism
作者:Jessica Neufeld、Timo Stünkel、Christian Mück‐Lichtenfeld、Constantin G. Daniliuc、Ryan Gilmour
DOI:10.1002/anie.202102222
日期:2021.6.7
discovery. To expand the current portfolio, the synthesis of novel trifluorinated tetralins has been achieved. Fluorinated methyleneindanes serve as convenient precursors and undergo efficient difluorinative ringexpansion with in situ generated p-TolIF2 (>20 examples, up to >95 %). A range of diverse substituents are tolerated under standard catalysis conditions and this is interrogated by Hammett analysis