Synthesis of β-Ketosulfonamides Derived from Amino Acids and Their Conversion to β-Keto-α,α-difluorosulfonamides via Electrophilic Fluorination
作者:Jacob Soley、Edmond Chiu、Ryan Chung、Jeremy Green、Jason E. Hein、Scott D. Taylor
DOI:10.1021/acs.joc.7b02179
日期:2017.10.20
β-Ketosulfonamides derived from Boc or Cbz-protected amino acids bearing hydrophobic side chains were prepared in good to excellent yield by treating N-allyl, N-alkyl methanesulfonamides with n-BuLi, followed by reaction of the resulting carbanion with methyl esters of N-protected l-amino acids. The analogous reaction using the dianion derived from an N-alkyl methanesulfonamide proceeded in much lower
通过处理β-Ketosulfonamides从Boc或衍生Cbz-保护的氨基酸轴承疏水性侧链以良好至优异的收率制备Ñ烯丙基,Ñ烷基methanesulfonamides与Ñ正丁基锂,接着用的甲酯所得到的碳负离子的反应Ñ -保护的1-氨基酸。使用源自N的二价阴离子的类似反应-烷基甲磺酰胺的产率要低得多。在CsF存在下,在DMF中于室温下使用Selectfluor进行β-酮磺酰胺的亲电氟化,反应时间为15-60分钟,可提供良好产率的β-酮-α,α-二氟磺酰胺。使用cat可以良好的产率除去烯丙基保护基。Pd(PPh)3)4和二甲基巴比妥酸。当以Cs 2 CO 3为碱进行氟化反应时,衍生自Val,Leu或Ile的β-酮磺酰胺给出了预期的β-酮-α,α-二氟磺酰胺,而衍生自Ala,Phe或hPhe的β-酮磺酰胺给出了亚氨基β-酮-α,α-二氟磺酰胺的水合物。