p-Toluenesulfonic Acid-Catalyzed Reaction of Phthalaldehydic Acids with Difluoroenoxysilanes: Access to 3-Difluoroalkyl Phthalides
作者:Jianguo Yang、Jun Ren、Saimei Liu、Yan Li、Feiyi Wang、Chao Ma、Guichun Yang
DOI:10.1055/a-1581-2408
日期:2022.1
A convenient approach for the synthesis of 3-difluoroalkyl phthalides has been developed from phthalaldehydic acids and difluoroenoxysilanes by using relatively inexpensive p-toluenesulfonic acid monohydrate (PTSA) as a catalyst. A series of 3-difluoroalkyl phthalides and cyclic difluoroalkyl ethers were obtained in up to 99% yield. The products obtained could be readily converted into difluoroalkyl
Enantioselective Synthesis of Difluoroalkylated Isoindolinones via Chiral Spirocyclic Phosphoric Acid Catalyzed Mannich-Type Reaction
作者:Xufeng Lin、Lei Wang、Jialing Zhong
DOI:10.1055/a-1274-2959
日期:2021.3
An enantioselective Mannich-type reaction of in situ generated cyclic ketimines with difluoroenoxysilanes catalyzed by chiral spirocyclic phosphoric acid has been developed. This methodology provides a facile route to difluoroalkyl-substituted chiral isoindolinones bearing a quaternary stereogenic center in high yields and up to 96% enantioselectivity.
A novel efficient HFIP-catalyzed synthesis of structurally diverse 2,2-difluoro-3-hydroxy-1,4-diketone derivatives from readily available glyoxalmonohydrates and difluoroenoxysilanes is described. This convenient protocol is induced by the distinctive fluorine effect of the reactants and the fluoroalcohol catalyst, which represents the first application of fluoroalcohol catalysis in a Mukaiyama aldol