Decarboxylative arylation with diaryliodonium(<scp>iii</scp>) salts: alternative approach for catalyst-free difluoroenolate coupling to aryldifluoromethyl ketones
α-Aryl-α,α-difluoroketones were synthesized via decarboxylative arylation using diaryliodonium salts under catalyst-free conditions without organometallic intermediates. The products can be transformed into various difluorinated functional groups.
N-heterocyclic carbene-catalyzed fluorinated silyl-Reformatsky reaction of aldehydes with difluoro (trimethylsilyl) acetate
作者:Ying Wang、Fen Xing、Cheng-Zhi Gu、Wen-Juan Li、Lin He、Bin Dai、Guang-Fen Du
DOI:10.1016/j.tet.2017.06.027
日期:2017.7
N-Heterocyclic carbenes (NHCs) have been employed as highly efficient organocatalysts for fluorinated silyl-Reformatsky reaction of carbonyl compounds. In the presence of 5–10 mol % NHC A, various aldehydes and 2,2,2–trifluoroacetophenone reacted with difluoro (trimethylsilyl) acetate to produce β–hydroxy gem–difluoro esters in 20–96% yields.
Synthesis of optically active gem-difluorinated organic molecules attracts a great deal of interest due to their unique properties in pharmaceutical and agrochemical areas. Herein, a series of enantioenriched α,α-difluoro-β-arylbutanoic esters were prepared in high yields (83–99%) with moderate to excellent enantioselectivities (≤97:3 er) by palladium-catalyzed asymmetrichydrogenation.