Synthesis of secondary difluoromethylphosphonate-contaning amino acid and its biological examination

蛋白质的磷酸化和去磷酸化作为翻译后修饰，对细胞内信号转译至关重要。因此，含非水解磷氨基酸模拟肽作为探索信号事件的有用试剂受到了广泛关注。在各种不可水解的磷酸氨基酸类似物中，那些采用二氟乙烯单元（CF2）作为磷酰酯氧的替代品的类似物已显示出特殊的用途。我们已经合成了cf2取代的pTyr和pSer模拟物；然而，合成2-氨基- 4,4 -二氟-3-甲基-4-膦丁酸（F2Pmab）作为cf2取代的pThr模拟物是很困难的。在本研究中，我们通过cecl3介导的偶联方式将二氟甲基膦酸二乙酯阴离子加成到硝基烯烃上，制备了外消旋保护的F2Pmab。此外，我们还利用cu介导的（二乙基膦二氟甲基）-溴化锌与β-碘-α， β-不饱和羧酸衍生物的偶联反应，完成了F2Pmab所有四种异构体的立体选择性合成，然后在手性助剂的帮助下进行非对映选择性氢化和胺化。利用由高酸性和低酸性试剂组成的两步脱保护方法，成功地将受保护的氨基酸衍生物纳入肽中。对于高酸性试剂，TFA体系中使用1 M tmsotf -硫代异唑，0.3 M

Phosphorylation and dephosphorylation of proteins serve as post-translational modifications that are critical for intracellular signal transudation. Therefore, nonhydrolyzable phosphoamino acid mimetic-containing peptides have gained much attention as useful agents for exploring signaling events. Among various nonhydrolyzable phosphoamino acid analogs, those employing the difluoromethylene unit (CF2) as a replacement for the phosphoryl ester oxygen have shown particular utility. We have already achieved the synthesis of CF2-substituted pTyr and pSer mimetics; however, synthesis of 2-amino-4, 4-difluoro-3-methy1-4-phosphonobutanoic acid (F2Pmab) as a CF2-substituted pThr mimetic was lacing. In this study, we accomplished the preparation of racemic protected F2Pmab by CeCl3-mediated conjugate addition of diethyl difluoromethylphosphonate anion onto a nitroalkene. Furthermore, we accomplished the stereoselective synthesis of all four F2Pmab isomers by applying Cu-mediated coupling reaction of (diethylphosphonodifluoromethyl) -zinc bromide with β-iodo-α, β- unsatureted carboxylic acid derivatives, followed by diastereoselective hydrogenation and amination with the aid of a chiral auxiliary. The protected amino acid derivative was successfully incorporated into peptides using a two-step deprotection methodology consisting of high acidic-and low acidic reagents. For high acidic reagents, 1 M TMSOTf-thioanisole in TFA system was used, and 0.3 M