Luo Z, Williams J, Read R W, Curran D P
Department of Chemistry and Center for Combinatorial Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
J Org Chem. 2001 Jun 15;66(12):4261-6. doi: 10.1021/jo010111w.
The first fluorous variants of the Boc (tert-butyloxycarbonyl) group have been prepared and tested for their suitability as nitrogen protecting groups. A group with two fluorous chains and an ethylene spacer, (RfCH2CH2)2(CH3)COC(O)-, was readily attached to a representative amine but was difficult to cleave. In contrast, groups with two fluorous chains and a propylene spacer, (RfCH2CH2CH2)2(CH3)COC(O)-, or one fluorous chain and an ethylene spacer, (RfCH2CH2)(CH3)2COC(O)-, were readily formed and cleaved. The fluorous alcohol component of the (F)Boc group can be removed by evaporation and can be recovered and reused. The utility of the new (F)Boc group (C8F17CH2CH2)(CH3)2COC(O)- was demonstrated in 16 and 96 compound library synthesis exercises. Separations can be achieved either by manual, parallel fluorous solid-phase extraction, or automated, serial fluorous chromatography. The results provide additional confirmation of the value of "light" fluorous synthesis techniques, and the new fluorous Boc groups expand the applicability of fluorous synthesis techniques to many classes of nitrogen-containing organic compounds.
已制备出Boc（叔丁氧羰基）基团的首批氟代变体，并对其作为氮保护基团的适用性进行了测试。带有两条氟代链和一个乙烯间隔基的基团，即(RfCH2CH2)2(CH3)COC(O)-，很容易连接到代表性胺上，但难以裂解。相比之下，带有两条氟代链和一个丙烯间隔基的基团，即(RfCH2CH2CH2)2(CH3)COC(O)-，或带有一条氟代链和一个乙烯间隔基的基团，即(RfCH2CH2)(CH3)2COC(O)-，很容易形成且易于裂解。(F)Boc基团的氟代醇组分可通过蒸发除去，并可回收再利用。新型(F)Boc基团(C8F17CH2CH2)(CH3)2COC(O)-在16和96化合物库合成实验中得到了验证。分离可通过手动平行氟代固相萃取或自动串联氟代色谱法实现。这些结果进一步证实了“轻量级”氟代合成技术的价值，并且新型氟代Boc基团将氟代合成技术的适用性扩展到了许多类含氮有机化合物。
