Copper-Catalyzed C(sp<sup>2</sup>)–H Difluoroalkylation of Aldehyde Derived Hydrazones with Diboron as Reductant
作者:Miaolin Ke、Qiuling Song
DOI:10.1021/acs.joc.6b00324
日期:2016.5.6
An efficient and general method for C(sp2)–Hdifluoroalkylation of aldehyde derived hydrazones via a CuII/B2pin2-catalyzed reaction between difluoroalkylbromides and hydrazones was developed. In this reaction, both aromatic and aliphatic difluoroalkylated aldehyde derived hydrazones could be achieved in good to excellent yields. For some heteroaromatic aldehyde derived hydrazones, two fluoroacetates
通过Cu II / B 2 pin 2催化的二氟烷基溴与的反应,开发了一种有效且通用的醛衍生的C(sp 2)-H二氟烷基化方法。在该反应中,芳族和脂族二氟烷基化醛衍生的azo均可以良好至优异的产率获得。对于某些杂芳族醛衍生的azo,可以将两种氟乙酸酯引入最终产物中。初步的机理研究表明,通过SET途径的二氟烷基自由基参与了反应。另外,催化二硼试剂在该转化中起着不可或缺的作用。
A convenient method for the preparation of α,α-difloro-β-ketoesters and α,α-difluoroamides from terpenic and perfumery aldehydes
Reformatsky reactions with ethyl bromodifluoroacetate gave α,α-difluoro-β-hydroxyesters in good yield from the corresponding terpenic and perfumery aldehydes. α,α-Difluoro-β-ketoesters were prepared by Swern oxidation of the α,α-difluoro-β-hydroxyesters. The reaction of hydroxyesters with amines in the presence of lipase MY, lipase PS or Novozym 435 gave α,α-difluoroamides.
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.
Organocatalytic aldol and domino Michael-aldol reactions of α,α-difluoro-β-keto esters with acetone
作者:Yan Zhao、Xiao-Jin Wang、Chen-Xin Cai、Jin-Tao Liu
DOI:10.1016/j.jfluchem.2014.06.010
日期:2014.9
Organocatalyzed reactions of α,α-difluoro-β-ketoesters with acetone were demonstrated. In the presence of L-proline, the Aldolreaction occurred under mild conditions to give the corresponding tertiary α,α-difluoroalcohols in good yields with high enantioselectivities. Using pyrrolidine as catalyst, the domino Michael-aldol reaction took place readily to give the corresponding addition products in